tag:theconversation.com,2011:/id/topics/paleontology-633/articlesPaleontology – The Conversation2024-03-27T12:37:29Ztag:theconversation.com,2011:article/2232682024-03-27T12:37:29Z2024-03-27T12:37:29ZHorses lived in the Americas for millions of years – new research helps paleontologists understand the fossils we’ve found and those that are missing from the record<figure><img src="https://images.theconversation.com/files/574775/original/file-20240211-26-t88v8r.jpg?ixlib=rb-1.1.0&rect=63%2C121%2C4179%2C2650&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People have collected fossil horses throughout North America for centuries.</span> <span class="attribution"><span class="source">Florida Museum/Mary Warrick</span></span></figcaption></figure><p>Many people assume that horses first came to the Americas when Spanish explorers brought them here about 500 years ago. In fact, recent research has <a href="https://theconversation.com/archaeology-and-genomics-together-with-indigenous-knowledge-revise-the-human-horse-story-in-the-american-west-202222">confirmed a European origin</a> for horses associated with humans in the American Southwest and Great Plains.</p>
<p>But those weren’t the first horses in North America. The family Equidae, which includes domesticated varieties of horses and donkeys along with zebras and their kin, is actually native to the Americas. The <a href="https://doi.org/10.1126/science.1105458">fossil record reveals</a> horse origins here more than 50 million years ago, as well as their extinction throughout the Americas during the last Ice Age about 10,000 years ago.</p>
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<a href="https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="family tree showing horse evolution diversifying over time" src="https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=741&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=741&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=741&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=932&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=932&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584586/original/file-20240326-30-4szthv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=932&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Phylogeny, geographic distribution, diet and body sizes of the family Equidae over the past 55 million years.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1126/science.1105458">From 'Fossil horses–evidence for evolution.' Science. MacFadden, 2005. Reprinted with permission from AAAS.</a></span>
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<p>We are <a href="https://scholar.google.com/citations?user=xhm6ez4AAAAJ&hl=en&oi=ao">paleontologists</a> <a href="https://scholar.google.com/citations?user=oZ8oBigAAAAJ&hl=en&oi=ao">who focus our research</a> on various types of fossils, including ancient horses. <a href="https://doi.org/10.1017/pab.2023.35">Our most recent work</a> used computer statistics to analyze gaps in the fossil record to infer more about which horse species really did and didn’t live in one ancient habitat in Florida.</p>
<h2>Horses evolved as ecosystems changed</h2>
<p>People have collected fossil horses throughout North America for centuries. Because horse fossils are abundant and widespread across the continent, scientists often point to the <a href="https://www.cambridge.org/us/universitypress/subjects/earth-and-environmental-science/palaeontology-and-life-history/fossil-horses-systematics-paleobiology-and-evolution-family-equidae?format=PB">long span of the horse family</a> as evidence of long-term evolutionary change.</p>
<p>Paleontologists like us, who study extinct mammals, almost never find complete skeletons. Instead, we focus on durable fossil teeth, which help us understand ancient diets, and fossil limbs, which help clarify how these animals moved.</p>
<p>Horses are eating machines. In the wild today, they primarily feed on grasses that don’t provide much nutrition, and thus they need to consume large quantities to survive. The large teeth of modern horses and their ancestors are adapted primarily for grazing on gritty grasses. They replaced smaller teeth of more primitive horses adapted to <a href="https://doi.org/10.1016/S0031-0182(01)00359-5">browsing on soft leafy vegetation</a>.</p>
<p>We know what horses ate millions of years ago by studying distinctive microscopic scratches, pits and other wear patterns on their teeth that were created <a href="https://doi.org/10.1016/j.palaeo.2015.11.004">as the ancient horses chewed plant foods</a>. And analyses of carbon preserved in fossil teeth show that <a href="https://doi.org/10.1016/0031-0182(94)90099-X">coexisting horse species ate different plants</a>; some browsed on leaves from bushes and trees, some grazed on grasses, and yet others were mixed feeders.</p>
<p>The change in tooth shape tracks the change in dominant vegetation types in North America, from tropical forests that then gave way to the <a href="https://doi.org/10.1146/annurev-earth-040809-152402">great expansion of open prairie grasslands</a>. As the climate and flora changed over millions of years, horses shifted from being largely forest-dwelling browsers to largely open-country grazers. Their teeth and feeding patterns adapted to the environment.</p>
<p>Another adaptation is visible on horses’ feet. Modern horses have one hoofed toe on each foot. Many extinct fossil horses – the ancient ancestors of today’s horses – had three toes per foot. The single toe on each elongated foot is good for rapid and sustained running to evade predators and for long-distance seasonal migrations. The more ancient three-toed feet provided <a href="https://doi.org/10.1038/308179a0">stability on unstable or wet ground</a>. The adaptation from three toes to one was likely in response to changing habitats.</p>
<p>But even as the environment changed, one distinct species didn’t completely replace another overnight. The fossil record in North America documents periods millions of years ago when multiple horse species coexisted on the ancient landscapes. Species were of different sizes and had teeth equipped for munching different plants, so they weren’t competing directly for the same foods. Different habitats within these ancient ecosystems likely had some species more adapted to forests and others more adapted to grasslands.</p>
<h2>Understanding Florida’s fossil record</h2>
<p>Paleontologists have been collecting horse fossils in Florida for over 125 years. The Florida Museum of Natural History at the University of Florida, where we work, has more than 70,000 fossil horse specimens from more than a thousand locations across the state.</p>
<p>One of our more <a href="https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/sites/montbrook/">prolific fossil sites, Montbrook</a>, provides a glimpse of a 5.8 million-year-old ancient stream bed. It preserved more than 30 extinct mammals, including rhinos, elephants and carnivores, as well as hundreds of bones and teeth of fossil horses.</p>
<p>Although six horse species are known elsewhere in Florida, we have only found four so far at Montbrook. This smaller number of horse species perplexed us, <a href="https://doi.org/10.1017/pab.2023.35">so we decided to investigate</a>. Did the two “missing” horse species truly not live at Montbrook, or have scientists simply not discovered their fossil remains yet?</p>
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<a href="https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Representative fossil horse teeth of Florida" src="https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=784&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=784&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=784&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=985&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=985&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584451/original/file-20240326-26-8hew8y.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=985&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Each of the six fossil horse species (A-F) found in Florida have distinct teeth. Scale bar = 1 centimeter.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1017/pab.2023.35">Killingsworth & MacFadden, Paleobiology, 2024</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
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<p>We designed a theoretical model that compares Montbrook, with only four horse species, to other fossil sites in Florida that contain all six. Using a statistical technique that scientists call “<a href="https://www.lancaster.ac.uk/stor-i-student-sites/jack-trainer/bootstrapping-in-statistics/">bootstrapping</a>,” our computer essentially simulated continued fossil collecting over time. We generated 1,000 theoretical fossil collection events based on the fossil species counts from the sites where all six are present, to predict the probability of collecting the species that are currently missing at Montbrook.</p>
<p>Results from our simulation show that the two missing horse species at Montbrook were absent for different reasons. One of the horses is likely to be truly absent; the other may still be discovered with further excavation.</p>
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<a href="https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="About a dozen people focused on digging in soil a few feet below the surface of surrounding landscape." src="https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=555&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=555&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576220/original/file-20240216-26-vkk8pe.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=555&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Excavations are ongoing at the Montbrook fossil site in Florida.</span>
<span class="attribution"><span class="source">Florida Museum/Jeff Gage</span></span>
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<h2>Probing ‘gaps’ in the fossil record</h2>
<p>Knowing a species is absent is just as important as knowing when one is present at a fossil site. Absences may be indicators of underlying ecological and biological drivers changing population dynamics. Coupled with other types of analyses, researchers can apply this kind of predictive modeling across many fossil species and ancient landscapes.</p>
<p>Ever since <a href="https://www.britannica.com/biography/Charles-Darwin/Evolution-by-natural-selection-the-London-years-1836-42">Charles Darwin proposed his theory of evolution</a>, scientists have known that the fossil record is incomplete, resulting in gaps in our knowledge of the ancient past and evolutionary change. Paleontologists are challenged to explain these gaps, including which species were or were not present at particular fossil sites.</p>
<p>Gaps can result from certain materials, such as teeth and shells, which are often more durable than porous bone, fossilizing better than others. Likewise, different chemical conditions during fossilization, and even the amount of time spent collecting fossils at a particular site, <a href="https://doi.org/10.1016/j.earscirev.2023.104537">can contribute to the lack of knowledge</a>.</p>
<p>Fortunately, fossil horse teeth preserve quite well and are commonly found. As new discoveries are made, such as those from our ongoing excavations in Florida, they’ll help clarify and narrow gaps in the fossil record.</p><img src="https://counter.theconversation.com/content/223268/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce J. MacFadden receives funding from the US National Science Foundation. </span></em></p><p class="fine-print"><em><span>Stephanie Killingsworth does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Horse fossils are abundant and widespread across North America. Scientists often use their long history to illustrate how species evolve in response to a changing environment.Stephanie Killingsworth, Ph.D. Student in Geological Sciences, University of FloridaBruce J. MacFadden, Distinguished Professor and Director of Thompson Earth Systems Institute (TESI), University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2197082024-03-07T13:30:42Z2024-03-07T13:30:42ZTitanosaurs were the biggest land animals Earth’s ever seen − these plant-powered dinos combined reptile and mammal traits<figure><img src="https://images.theconversation.com/files/578965/original/file-20240229-28-gycuea.jpg?ixlib=rb-1.1.0&rect=26%2C0%2C3000%2C1967&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A replica fossil of the titanosaur _Patagotitan_, one of the largest dinosaurs ever discovered. It would have weighed about 70 tons (63.5 metric tons.)</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/replica-of-one-of-the-largest-dinosaurs-ever-discovered-is-news-photo/504972828">Spencer Platt/Getty Images News via Getty Images</a></span></figcaption></figure><p>You’re probably familiar with classic sauropod dinosaurs – the four-legged herbivores famous for their long necks and tails. Animals such as <a href="https://www.ucpress.edu/book/9780520246232/the-sauropods"><em>Brachiosaurus</em>, <em>Apatosaurus</em> and <em>Diplodocus</em></a> have been standard fixtures in science museums since the 1800s.</p>
<p>With their small brains and enormous bodies, these creatures have long been the poster children for <a href="https://www.scientificamerican.com/article/triumph-of-the-titans/">animals destined to go extinct</a>. But recent discoveries have completely rewritten the doomed sauropod narrative. </p>
<p><a href="https://scholar.google.com/citations?user=Dz3tM2YAAAAJ&hl=en">I study</a> a lesser known group of sauropod dinosaurs – the Titanosauria, or “titanic reptiles.” Instead of going extinct, <a href="https://doi.org/10.1007/978-3-030-95959-3_10">titanosaurs flourished</a> long after their more famous cousins vanished. Not only were they large and in charge on <a href="https://paleobiodb.org/navigator/">all seven continents</a>, they held their own amid the <a href="https://doi.org/10.1016/j.palaeo.2017.10.035">newly evolved duck-billed and horned dinosaurs</a>, until an <a href="https://doi.org/10.1126/science.aay2268">asteroid struck Earth</a> and ended the age of dinosaurs.</p>
<p>The secret to titanosaurs’ remarkable biological success may be how they merged the best of both reptile and mammal characteristics to form a unique way of life. </p>
<h2>Moving with the continents</h2>
<p>Titanosaurs <a href="https://doi.org/10.1111/j.1096-3642.2012.00853.x">originated by the Early Cretaceous Period</a>, nearly 126 million years ago, at a time when many of the <a href="https://deeptimemaps.com/map-lists-thumbnails/global-paleogeography-and-tectonics-in-deep-time/">Earth’s landmasses were much closer together</a> than they are today.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/HhkyXrWNoVA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Starting about 200 million years ago, the supercontinent Pangea began to break apart and drift.</span></figcaption>
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<p>Over the next 75 million to 80 million years, the <a href="https://theconversation.com/how-earths-continents-became-twisted-and-contorted-over-millions-of-years-116168">continents slowly separated</a>, and titanosaurs drifted along with the changing formations, becoming distributed worldwide. </p>
<p>There were nearly <a href="https://doi.org/10.1007/978-3-030-95959-3_8">100 species of titanosaurs</a>, making up more than 30% of known sauropod dinosaurs. They varied greatly in size. From the largest known sauropods ever discovered, including <a href="https://doi.org/10.1080/08912960410001715132"><em>Argentinosaurus</em></a>, <a href="https://doi.org/10.1098/rspb.2017.1219"><em>Patagotitan</em></a> and <a href="https://doi.org/10.1590/S0001-37652007000300013"><em>Futalognkosaurus</em></a>, whose weight exceeded 60 tons (54.4 metric tons) and were bigger than a semitruck, to the smallest known sauropods, including <a href="https://doi.org/10.1016/j.cretres.2022.105389"><em>Rinconsaurus</em></a>, <a href="https://doi.org/10.1016/j.cretres.2014.12.012"><em>Saltasaurus</em></a> and <a href="https://doi.org/10.1073/pnas.1000781107"><em>Magyarosaurus</em></a>, which were around only 6 tons (5.4 metric tons) and about the size of an African elephant. </p>
<h2>Babies to titans</h2>
<p>Like many reptiles, titanosaurs began life comparatively tiny, hatching from <a href="https://doi.org/10.1038/24370">eggs no bigger than grapefruits</a>.</p>
<p>The <a href="https://doi.org/10.1038/24370">best data on titanosaur nests</a> and eggs comes from a site in Argentina called Auca Mahuevo, featuring 75 million-year-old exposed rocks. The site contains hundreds of fossilized nests containing thousands of eggs, some of which are so well preserved, scientists recovered <a href="https://doi.org/10.1666/05-150.1">skin impressions from ancient embryos</a>.</p>
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<a href="https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white microscopic image showing a bumpy pattern." src="https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579040/original/file-20240229-20-4s0o47.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The fossilized skin of a titanosaur embryo discovered in Argentina.</span>
<span class="attribution"><span class="source">Courtesy of L. M. Chiappe, Natural History Museum of Los Angeles County</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>The sheer number of nests found together, in multiple geological layers, suggests titanosaurs <a href="https://doi.org/10.1016/j.palaeo.2013.05.031">returned to this site repeatedly</a> to lay their eggs. The nests are so closely spaced, it’s unlikely an adult titanosaur would have been able to move freely through the nesting ground. Titanosaurs likely had a hands-off parenting style, similar to many reptiles that lay numerous eggs and don’t spend much time tending the nest or taking care of hatchlings. </p>
<p><a href="https://doi.org/10.1126/science.aaf1509">A titanosaur hatchling</a> would have been roughly 1 foot (30 centimeters) tall, 3 feet (1 meter) long and 5-10 pounds (2.5-5 kg). Recent evidence from a site in Madagascar suggests these tiny titans were born ready to rumble.</p>
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<a href="https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration of a human standing next to five different sized 4-legged, long necked dinosaurs from an baby to towering individual." src="https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=259&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=259&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=259&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=325&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=325&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569145/original/file-20240112-19-8vmjcx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=325&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A titanosaur from Madagascar called <em>Rapetosaurus krausei</em> is known from fossils of tiny hatchlings, giant adults and a variety of in-between sizes.</span>
<span class="attribution"><span class="source">Jordan Mae Harris</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>Fossilized bones from the species <em>Rapetosaurus</em> suggest that by the time they would have been just knee high to a modern human, they were <a href="https://doi.org/10.1126/science.aaf1509">likely fending for themselves</a>. Microscopic details recorded deep within the bones indicate baby <em>Rapetosaurus</em> likely foraged independently for plants and moved much more nimbly than their lumbering adult relatives.</p>
<p>For the first century of dinosaur science, paleontologists imagined titanosaurs as giant, overgrown reptiles – and <a href="https://www.jstor.org/stable/2400208">used reptilian growth rates to predict their milestones</a>. In this slow-growth model, even the smallest titanosaurs would have taken nearly a century to reach their full size, meaning they would have been relatively small for a good chunk of their lives. New evidence suggests this growth pattern is unlikely.</p>
<p>Scientists like me <a href="https://www.ucpress.edu/book/9780520273528/bone-histology-of-fossil-tetrapods">study titanosaurs’ bones at high magnification</a> to better understand their growth. We look at the microscopic patterns of bone minerals as well as the density and architecture of the spaces that held blood vessels and cells. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A microscopic image showing both horizontal wavy spaces and circular spaces against a solid background." src="https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579902/original/file-20240305-24-l3albd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A thin slice of a juvenile titanosaur femur bone. The linear and circular structures are the spaces where a dense network of blood vessels supplied this fast-growing animal with plenty of nutrients.</span>
<span class="attribution"><span class="source">Kristi Curry Rogers</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The more dense the blood supply is to a bone, the faster that animal grows. These signatures are also present in living animals and can accurately reflect <a href="https://doi.org/10.1201/9781351189590">growth rates, anomalies and even age</a>. </p>
<p>Bone data shows titanosaur growth rates were <a href="https://doi.org/10.1201/9781351189590">on par with mammals like whales</a> – much, much faster than any living reptile – meaning they would have reached their enormous adult sizes <a href="https://doi.org/10.1111/j.1469-185X.2010.00137.x">in just a few decades</a>. Scientists can’t know for sure how long titanosaurs lived, but based on large land animals living today, titanosaurs lived possibly 60 or more years. </p>
<h2>Fueled by plants</h2>
<p>The rapid growth rates of sauropods was partly due to their body temperatures. By studying the chemistry of fossilized teeth <a href="https://doi.org/10.1038/ncomms9296">and eggshells</a>, scientists have determined titanosaurs had body temperatures <a href="https://doi.org/10.1126/science.1206196">ranging from about 95 to 100.5 degrees Fahrenheit</a> (35 to 38 degrees Celsius). That’s higher than that of crocodiles and alligators, about the same as modern mammals and a bit lower than most birds, whose bodies can regularly get <a href="https://doi.org/10.1016/0300-9629(91)90122-S">as warm as 104 F (40 C)</a>.</p>
<p>Titanosaurs’ rapid growth rates were also powered by their prodigious appetites for plants. Microscopic patterns of scratches, wear and pits on their teeth indicate titanosaurs in Argentina fed on a diverse diet rich in grit, suggesting they were <a href="https://doi.org/10.1371/journal.pone.0151661">dining on plants found lower to the ground</a>, where sediment would be more commonly found.</p>
<p>In India, chunks of fossilized feces, <a href="https://theconversation.com/ancient-poop-offers-unusual-insight-into-animal-behaviour-197200">otherwise known as coprolites</a>, show titanosaurs there ingested everything from <a href="https://doi.org/10.1126/science.1118806">ground-level plants all the way up to the leaves and branches</a> of trees.</p>
<p>Like all dinosaurs, titanosaurs replaced their teeth throughout life. But data shows they replaced each tooth <a href="https://doi.org/10.1371/journal.pone.0069235">about every 20 days</a> for maximum efficiency, one of the highest tooth-replacement rates known for dinosaurs.</p>
<p>Had it not been for the <a href="https://doi.org/10.1126/science.1177265">asteroid impact 66 million years ago</a>, these long-lived, incredibly diverse and wildly successful animals probably would have kept on thriving, in places as distant as <a href="https://paleobiodb.org/navigator/">Madagascar, Romania, North America and even Antarctica</a>. Instead, titanosaurs were among the witnesses to – and victims of – the most recent mass extinction on Earth.</p><img src="https://counter.theconversation.com/content/219708/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kristi Curry Rogers receives funding from the National Science Foundation and the David B. Jones Foundation. </span></em></p>Some of these giant vegetarians were as tall as a 3-story building. Microscopic analysis of their teeth, bones and eggshells reveals how they grew, what they ate and even their body temperature.Kristi Curry Rogers, Professor of Biology and Geology, Macalester CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2193972024-02-06T21:38:09Z2024-02-06T21:38:09ZA 380-million-year old predatory fish from Central Australia is finally named after decades of digging<figure><img src="https://images.theconversation.com/files/568893/original/file-20240111-21-jl663h.jpg?ixlib=rb-1.1.0&rect=609%2C0%2C2039%2C1138&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Harajicadectes cruises through the ancient rivers of central Australia ~385 million years ago.</span> <span class="attribution"><span class="source">Brian Choo</span></span></figcaption></figure><p>More than 380 million years ago, a sleek, air-breathing predatory fish patrolled the rivers of central Australia. Today, the sediments of those rivers are outcrops of red sandstone in the remote outback.</p>
<p>Our new paper, published in the <a href="https://www.tandfonline.com/doi/full/10.1080/02724634.2023.2285000">Journal of Vertebrate Paleontology</a>,
describes the fossils of this fish, which we have named <em>Harajicadectes zhumini</em>. </p>
<p>Known from at least 17 fossil specimens, <em>Harajicadectes</em> is the first reasonably complete bony fish found from Devonian rocks in central Australia. It has also proven to be a most unusual animal.</p>
<h2>Meet the biter</h2>
<p>The name means “Min Zhu’s Harajica-biter”, after the location where its fossils were found, its presumed predatory habits, and in honour of eminent Chinese palaeontologist <a href="http://english.ivpp.cas.cn/people/members/202305/t20230530_331150.html">Min Zhu</a>, who has made many contributions to <a href="https://theconversation.com/a-kung-fu-kick-led-researchers-to-the-worlds-oldest-complete-fish-fossils-heres-what-they-found-190749">early vertebrate research</a>. </p>
<p><em>Harajicadectes</em> was a fish in the <a href="https://en.wikipedia.org/wiki/Tetrapodomorpha">Tetrapodomorpha</a> group. This group had strongly built paired fins and usually only a single pair of external nostrils.</p>
<p>Tetrapodomorph fish from the Devonian period (359–419 million years ago) have long been of great interest to science. They include the forerunners of modern tetrapods – animals with backbones and limbs such as amphibians, reptiles, birds and mammals.</p>
<p>For example, recent fossil discoveries show fingers and toes arose <a href="https://www.nature.com/articles/s41586-020-2100-8">in this group</a>. </p>
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Read more:
<a href="https://theconversation.com/when-fish-gave-us-the-finger-this-ancient-four-limbed-fish-reveals-the-origins-of-the-human-hand-129072">When fish gave us the finger: this ancient four-limbed fish reveals the origins of the human hand</a>
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<p>Devonian fossil sites in <a href="https://www.youtube.com/watch?v=LnHVPgvrn2M">northwestern</a> and <a href="https://australian.museum/learn/australia-over-time/fossils/sites/canowindra/">eastern</a> Australia have produced many spectacular discoveries of early tetrapodomorphs.</p>
<p>But until our discovery, the poorly sampled interior of the continent had only offered tantalising fossil fragments. </p>
<h2>A long road to discovery</h2>
<p>Our species description is the culmination of 50 years of tireless exploration and research. </p>
<p>Palaeontologist Gavin Young from the Australian National University made the initial discoveries in 1973 while exploring the Middle-Late Devonian Harajica Sandstone on Luritja/Arrernte country, more than 150 kilometres west of Alice Springs (Mparntwe).</p>
<p>Packed within red sandstone blocks on a remote hilltop were hundreds of fossil fishes. The vast majority of them were small <em>Bothriolepis</em> – a type of widespread prehistoric fish known as a <a href="https://en.wikipedia.org/wiki/Placodermi">placoderm</a>, covered in box-like armour.</p>
<p>Scattered among them were fragments of other fishes. These included <a href="https://bioone.org/journals/Acta-Palaeontologica-Polonica/volume-54/issue-4/app.2008.0057/A-New-Genus-of-Lungfish-from-the-Givetian-Middle-Devonian/10.4202/app.2008.0057.full">a lungfish known as <em>Harajicadipterus youngi</em></a>, named in honour of Gavin Young and his years of work on material from Harajica.</p>
<p>There were also spines from acanthodians (small, vaguely shark-like fish), the plates of phyllolepids (extremely flat placoderms) and, most intriguingly, jaw fragments of a previously unknown tetrapodomorph. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565947/original/file-20231215-21-3lshgi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The moment of discovery when we found a complete fossil of <em>Harajicadectes</em> in 2016. Flinders University palaeontologists John Long (centre), Brian Choo (right) and Alice Clement (left) with ANU palaeontologist Gavin Young (top left).</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>Many more partial specimens of this Harajica tetrapodomorph were collected in 1991, including some by the late palaeontologist <a href="https://www.smh.com.au/national/the-man-who-found-4000-fish-fossils-in-a-nsw-country-town-20231205-p5ep2m.html">Alex Ritchie</a>.</p>
<p>There were early attempts at figuring out the species, but this proved troublesome. Then, our Flinders University expedition to the site in 2016 yielded the first almost complete fossil of this animal.</p>
<p>This beautiful specimen demonstrated that all the isolated bits and pieces collected over the years belonged to a single new type of fish. It is now in the collections of the Museum and Art Gallery of the Northern Territory, serving as the <a href="https://museum.wa.gov.au/explore/blogs/museumcollections/what-type-specimen">type specimen</a> of <em>Harajicadectes</em>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sandstone image of a fish shape along with two graphics showing it in more detail" src="https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567575/original/file-20240102-21-i0b5nl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The type specimen of <em>Harajicadectes</em> discovered in 2016.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<h2>A strange apex predator</h2>
<p>Up to 40 centimetres long, <em>Harajicadectes</em> is the biggest fish found in the Harajica rocks. Likely the top predator of those ancient rivers, its big mouth was lined with closely-packed sharp teeth alongside larger, widely spaced triangular fangs.</p>
<p>It seems to have combined anatomical traits from different tetrapodomorph lineages via convergent evolution (when different creatures evolve similar features independently). An example of this are the patterns of bones in its skull and scales. Exactly where it sits among its closest relatives is difficult to resolve. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large fish seen on the bottom of the sea with two smaller armoured fish underneath it" src="https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=781&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=781&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=781&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=981&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=981&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569190/original/file-20240114-27-x8x87i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=981&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Artist’s reconstruction of <em>Harajicadectes</em> menacing a pair of armoured <em>Bothriolepis</em>.</span>
<span class="attribution"><span class="source">Artist: Brian Choo</span></span>
</figcaption>
</figure>
<p>The most striking and perhaps most important features are the two huge openings on the top of the skull called spiracles. These typically only appear as minute slits in most early bony fishes.</p>
<p>Similar giant spiracles also appear in <a href="https://en.wikipedia.org/wiki/Gogonasus"><em>Gogonasus</em></a>, a marine tetrapodomorph from the famous Late Devonian Gogo Formation of Western Australia. (It doesn’t appear to be an immediate relative of <em>Harajicadectes</em>.)</p>
<p>They are also seen in the unrelated <a href="https://onlinelibrary.wiley.com/doi/am-pdf/10.1002/spp2.1243"><em>Pickeringius</em></a>, an early ray-finned fish that was also at Gogo.</p>
<h2>The earliest air-breathers?</h2>
<p>Other Devonian animals that sported such spiracles were the famous elpistostegalians – freshwater tetrapodomorphs from the Northern Hemisphere such as <a href="https://en.wikipedia.org/wiki/Elpistostege"><em>Elpistostege</em></a> and <a href="https://en.wikipedia.org/wiki/Tiktaalik"><em>Tiktaalik</em></a>.</p>
<p>These animals were extremely close to the ancestry of limbed vertebrates. So, enlarged spiracles seem to have arisen independently in at least four separate lineages of Devonian fishes.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=628&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=628&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=628&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=789&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=789&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567607/original/file-20240102-21-evllkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=789&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The skull of <em>Harajicadectes</em> seen from above, showing the enormous spiracles.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>The only living fishes with similar structures are bichirs, African ray-finned fishes that live in shallow floodplains and estuaries. It was recently confirmed <a href="https://theconversation.com/now-listen-air-breathing-fish-gave-humans-the-ability-to-hear-21324">they draw surface air through their spiracles</a> to aid survival in oxygen-poor waters.</p>
<p>That these structures appeared roughly simultaneously in four Devonian lineages provides a fossil “signal” for scientists attempting to reconstruct atmospheric conditions in the distant past.</p>
<p>It could help us uncover the evolution of air breathing in backboned animals.</p><img src="https://counter.theconversation.com/content/219397/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Choo receives funding from the Australian Research Council and is employed by Flinders University.</span></em></p><p class="fine-print"><em><span>Alice Clement receives funding from the Australian Research Council and is employed by Flinders University.</span></em></p><p class="fine-print"><em><span>John Long receives funding from The Australian Research Council.</span></em></p>For decades, the sandstone in central Australia yielded tantalising segments of some sort of fossil fish. Now, we have finally pieced together a complete picture of this remarkable species.Brian Choo, Postdoctoral fellow in vertebrate palaeontology, Flinders UniversityAlice Clement, Research Associate in the College of Science and Engineering, Flinders UniversityJohn Long, Strategic Professor in Palaeontology, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2214822024-01-24T19:01:54Z2024-01-24T19:01:54ZA newly identified ‘Hell chicken’ species suggests dinosaurs weren’t sliding toward extinction before the fateful asteroid hit<figure><img src="https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&rect=386%2C718%2C3592%2C2613&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Birdlike dinosaur *Eoneophron infernalis* was about the size of an adult human. </span> <span class="attribution"><span class="source">Zubin Erik Dutta</span></span></figcaption></figure><p>Were dinosaurs already on their way out when an asteroid hit Earth 66 million years ago, ending the <a href="https://www.britannica.com/science/Cretaceous-Period">Cretaceous</a>, the geologic period that started about 145 million years ago? It’s a question that has vexed <a href="https://scholar.google.com/citations?user=Yqc3u-gAAAAJ&hl=en&oi=ao">paleontologists</a> <a href="https://scholar.google.com/citations?user=RCWbDQQAAAAJ&hl=en&oi=ao">like us</a> for more than 40 years.</p>
<p>In the late 1970s, debate began about whether dinosaurs were at their peak or in decline before their big extinction. Scientists at that time noted that while dinosaur diversity seemed to have increased in the geologic stage that spanned 83.6 million to 71.2 million years ago, the <a href="https://doi.org/10.1126/science.232.4750.629">number of species on the scene</a> seemed to decrease during the last few million years of the Cretaceous. Some researchers have interpreted this pattern to mean that the <a href="https://theconversation.com/more-bad-news-for-dinosaurs-chicxulub-meteorite-impact-triggered-global-volcanic-eruptions-on-the-ocean-floor-91053">asteroid that struck the Gulf of Mexico</a> was <a href="https://doi.org/10.1073/pnas.1521478113">simply the final blow</a> <a href="https://doi.org/10.1038/s41467-021-23754-0">for an already vulnerable group of animals</a>.</p>
<p>However, others have argued that what looks like a decrease in <a href="https://doi.org/10.1038/307360a0">the diversity of dinosaurs</a> may be an artifact of <a href="https://doi.org/10.1098/rsos.201195">how hard it is to accurately count them</a>. Fossil formations might <a href="https://doi.org/10.1073/pnas.0606028103">preserve different dinosaurs more or less often</a> based on factors like their favored environment and how easily their bodies fossilized there. The accessibility of various outcrops could influence what kinds of fossils researchers have so far found. These biases are a problem because fossils are what paleontologists must rely on to conclusively answer how healthy dinosaur populations were when the asteroid hit.</p>
<p>At that crucial moment, what was really happening to dinosaur diversity? Discovery, identification and description of new dinosaurs provide vital clues. This is where <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0294901">our work</a> comes in. Close examination of what we’d thought was a juvenile specimen of an already known species of dinosaur from this time period revealed that it was actually part of an adult from a completely new species. </p>
<p>Our work focusing on the life stage of our specimen demonstrates that dinosaur diversity may not have been declining before the asteroid hit, but rather that there are more species from this time period yet to be discovered – potentially even through reclassification of fossils already in museum collections.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="hand on one of three long fossil bones with a ruler" src="https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570889/original/file-20240123-21-ep8hu1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Kyle Atkins-Weltman holds the femur of the new dinosaur as it was received, with the other fossils in the background.</span>
<span class="attribution"><span class="source">Kyle Atkins-Weltman</span></span>
</figcaption>
</figure>
<h2>Clues inside the bones of a birdlike dinosaur</h2>
<p>Our new study focused on four hindlimb bones – a <a href="https://www.britannica.com/science/femur">femur</a>, a <a href="https://www.britannica.com/science/tibia">tibia</a> and two <a href="https://www.britannica.com/science/metatarsal">metatarsals</a>. They were unearthed in South Dakota, in rocks of the <a href="https://ucmp.berkeley.edu/science/parks/hellcreek.php">Hell Creek Formation</a>, and date to the final 2 million years of the Cretaceous.</p>
<p>When we first examined the bones, we identified them as belonging to a family of dinosaurs known as the caenagnathids – a group of birdlike dinosaurs that had toothless beaks, long legs and short tails. <a href="https://doi.org/10.1080/08912963.2020.1726908">Direct</a> <a href="https://doi.org/10.1038/nature08965">fossil</a> <a href="https://doi.org/10.1038/35003103">and</a> <a href="https://www.infona.pl/resource/bwmeta1.element.agro-article-a7940458-6921-49de-8963-52892bc56dc8">inferred</a> <a href="https://doi.org/10.1371/journal.pone.0092022">evidence</a> <a href="https://experts.umn.edu/en/publications/section-1-systematics-fossil-record-and-biogeography-chapter-1-pe">indicates</a> <a href="https://experts.umn.edu/en/publications/chapter-2-the-fossil-record-of-mesozoic-and-paleocene-pennaraptor">these dinosaurs</a> were <a href="https://doi.org/10.1038/31635">covered in complex feathers</a>, much <a href="https://www.vertpala.ac.cn/EN/Y2000/V38/I04/241">like modern birds</a>.</p>
<p>The only known species of <a href="https://doi.org/10.1371/journal.pone.0092022">caenagnathid from this time and region</a> was <em>Anzu</em>, sometimes called the “<a href="https://www.theguardian.com/science/2014/mar/19/dinosaur-chicken-hell-anzu-wyliei">chicken from Hell</a>.” Covered in feathers and sporting wings and a toothless beak, <em>Anzu</em> was between roughly 450 and 750 pounds (200 and 340 kilograms). Despite its fearsome nickname, though, its diet is a matter of debate. It was likely an omnivore, eating both plant material and small animals.</p>
<p>Because our specimen was significantly smaller than <em>Anzu</em>, we simply assumed it was a juvenile. We chalked up the anatomical differences we noticed to its juvenile status and smaller size – and figured the animal would have changed had it continued to grow. <em>Anzu</em> specimens are rare, and no definite juveniles have been published in the scientific literature, so we were excited to potentially learn more about how it grew and changed throughout its lifetime <a href="https://doi.org/10.1525/california/9780520273528.003.0004">by looking inside its bones</a>.</p>
<p>Just like with a tree’s rings, <a href="https://doi.org/10.1126/sciadv.aax6250">bone records rings called lines of arrested growth</a>. Each annual line represents part of a year when the animal’s growth slowed. They would tell us how old this animal was, and how fast or slow it was growing.</p>
<p>We cut through the middle of three of the bones so that we could microscopically examine the internal anatomy of the cross-sections. What we saw <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0294901">completely uprooted our initial assumptions</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cross-section 'slice' of yellowish fossilized bone with growth lines like the rings of a tree" src="https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570996/original/file-20240123-17-53v1e0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Teal markers point to lines of arrested growth on the cross-section of fossilized bone. Toward the outside of the bone, the lines are much closer together, reflecting less growth per year. Researchers counted exactly six lines, meaning this animal was between 6 and 7 years old when it died.</span>
<span class="attribution"><span class="source">Holly Woodward</span></span>
</figcaption>
</figure>
<p>In a juvenile, we would expect lines of arrested growth in the bone to be widely spaced, indicating rapid growth, with even spacing between the lines from the inside to the outside surface of the bone. Here, we saw that the later lines were spaced progressively closer together, indicating that this animal’s growth had slowed and it was nearly at its adult size.</p>
<p>This was no juvenile. Instead, it was an adult of an entirely new species, which we dubbed <em>Eoneophron infernalis</em>. The name means “Pharaoh’s dawn chicken from Hell,” referencing the nickname of its larger cousin <em>Anzu</em>. Traits unique to this species include ankle bones fused to the tibia, and a well-developed ridge on one of its foot bones. These weren’t features a young <em>Anzu</em> would outgrow, but rather unique aspects of the smaller <em>Eoneophron</em>.</p>
<h2>Expanding the caenagnathid family tree</h2>
<p>With this new evidence, we started making thorough comparisons with other members of the family to determine where <em>Eoneophron infernalis</em> fit within the group.</p>
<p>It also inspired us to reexamine other bones previously believed to be <em>Anzu</em>, as we now knew that more caenagnathid dinosaurs lived in western North America during that time. One specimen, a partial foot bone smaller than our new specimen, appeared distinct from both <em>Anzu</em> and <em>Eoneophron</em>. Where once there was one “chicken from Hell,” now there were two, and evidence for a third: one large (<em>Anzu</em>), weighing as much as a grizzly bear, one medium (<em>Eoneophron</em>), humanlike in weight, and one small and yet unnamed, close in size to a German shepherd.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&rect=386%2C718%2C3592%2C2613&q=45&auto=format&w=1000&fit=clip"><img alt="wooded scene with three different sizes of bird-like dinosaur" src="https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&rect=386%2C718%2C3592%2C2613&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=561&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=561&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570405/original/file-20240119-25-cv46uw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=561&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Eoneophron infernalis</em> and the smaller unnamed species now join the larger <em>Anzu</em> as late-Cretaceous caenagnathid dinosaurs from the Hell Creek region.</span>
<span class="attribution"><span class="source">Zubin Erik Dutta</span></span>
</figcaption>
</figure>
<p>Comparing Hell Creek with older fossil formations <a href="https://doi.org/10.1080/08912963.2020.1726908">such as the famous Dinosaur Park Formation of Alberta</a> that preserves dinosaurs that <a href="https://doi.org/10.1038/s41598-022-19896-w">lived between 76.5 million and 74.4 million years ago</a>, we find not only the same number of caenagnathid species, but also the same size classes. There, we have <em>Caenagnathus</em>, comparable to <em>Anzu</em>, <em>Chirostenotes</em>, comparable to <em>Eoneophron</em>, and <em>Citipes</em>, comparable to the third species we found evidence for. These parallels in both species count and relative sizes offer compelling evidence that caenagnathids remained stable throughout the last part of the Cretaceous. </p>
<p>Our new discovery suggests that this dinosaur group was not declining in diversity at the very end of the Cretaceous. These fossils show that there are still new species to be discovered, and support the idea that at least part of the pattern of decreasing diversity is the result of sampling and preservation biases.</p>
<p>Did large dinosaurs go extinct the way a Hemingway character quipped he went broke: “<a href="https://cardinalinstitute.com/gradually-then-suddenly/">gradually, then suddenly</a>”? While there are plenty of questions still outstanding in this extinction debate, <em>Eoneophron</em> adds evidence that caenagnathids were doing quite well for themselves before the asteroid ruined everything.</p>
<p><em>This article has been updated to correct the full name in English of the new species.</em></p><img src="https://counter.theconversation.com/content/221482/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Rather than a juvenile of a known species, several fossilized bones represent a new species – and shed light on the question of whether dinosaurs were already in decline before disaster struck.Kyle Atkins-Weltman, Ph.D. Student in Paleoecology, Oklahoma State UniversityEric Snively, Associate Professor of Anatomy and Cell Biology, Oklahoma State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2115062023-09-04T02:35:55Z2023-09-04T02:35:55ZHow diving as a boy took Tim Flannery on the trail of the megalodon in all its ‘terrifying glory’<figure><img src="https://images.theconversation.com/files/545437/original/file-20230830-39956-lsjhr9.jpg?ixlib=rb-1.1.0&rect=77%2C11%2C3886%2C1970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tim Flannery with a model set of jaws of a megalodon at the Australian Museum, and, on right, a megalodon tooth.</span> <span class="attribution"><span class="source">Photos: Text Publishing, Wikimedia Commons</span></span></figcaption></figure><p>With <a href="https://www.imdb.com/title/tt9224104/">Meg 2: The Trench</a> currently showing in cinemas – its eponymous star looking unhelpfully like an oversized great white shark – megalodons are having another pop cultural moment.</p>
<p>Cinema-goers may, justifiably, have questions about the accuracy of this latest representation of these prehistoric creatures. The good news is that Tim and Emma Flannery have written a book that will both thrill and inform such curious readers.</p>
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<p><em>Review: Big Meg: The Story of the Largest and Most Mysterious Predator that Ever Lived – Tim Flannery and Emma Flannery (Text Publishing)</em></p>
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<p>Megalodons had cartilaginous structures, rather than the bony skeletons of the dinosaurs. While dinosaurs roamed Earth during the Triassic, Jurassic and Cretaceous periods (from 252 million to 66 million years ago), it is believed the megalodon emerged a mere 23 million years ago. </p>
<p>Megalodons had big, serrated teeth that could cut through large marine animals. When they became extinct, about 3.6 million years ago, palaeontologists were left only with remnants of their toothy smile from which to unpick the story of these sharks.</p>
<p>A palaeontologist by training, Tim Flannery’s prolific literary output has contributed both to academic debate and general awareness-raising about the nature and needs of the planet we continue to dominate. In this latest book, he has combined forces with his daughter, Emma, a scientist and explorer in her own right, but this is very much his story.</p>
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<a href="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=918&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=918&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=918&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1153&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1153&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1153&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<p>Text Publishing’s edition advertises Big Meg as: “The Story of the Largest and Most Mysterious Predator that Ever Lived”. While these words are intended to excite readers, scientists have not yet assigned a definitive shape or weight to the megalodon. How sure can we be that it was the largest predator? <a href="https://en.wikipedia.org/wiki/Livyatan">Livyatan</a>, for instance, a prehistoric sperm whale, was an estimated 17.5m long and sported the largest teeth of any known creature. </p>
<p>At any rate, Tim and Emma Flannery approach the mysterious megalodon with imagination and intelligent speculation. They draw on what is already known of other species of sharks, while accepting this one could have been quite different.</p>
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<em>
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Read more:
<a href="https://theconversation.com/ancient-megalodon-super-predators-could-swallow-a-great-white-shark-whole-new-model-reveals-188749">Ancient megalodon super-predators could swallow a great white shark whole, new model reveals</a>
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</em>
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<p>The book begins with an account of Tim as a teenage fossil-hunter in western Victoria. After unprecedented floods in 1973 expose a fresh layer of fossils for exploration, he finds a large megalodon tooth. From this moment, his passion is fired to find out more about this mysterious creature.</p>
<p>At the Museum of Victoria, Tim finds a curator who becomes his lifelong mentor. Tim had already found bits of a fossilised seal at Melbourne’s Beaumaris beach, so his mentor employs him to look for the rest of it on the understanding he must hand over anything he finds. On his first day’s dive, Tim discovers a beautiful, large, green megalodon tooth. He agonises over parting with it.</p>
<p>More than four decades later, he finds closure when he revisits this tooth at the museum. (Ironically, his mentor tells him: “I would have been happy for you to keep it.”) As he once more holds the tooth in his hand, reflecting on its rightful place in the museum’s collection, he realises he “had finally grown up”.</p>
<p>Throughout the book, Tim and Emma explore this tooth’s place in Earth’s emerging environments with an ease that comes with extensive knowledge of the subject. Drawing on comparative examples of fossilised prey, they imaginatively recreate the megalodon’s life in the ancient oceans as an apex predator. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Tim and Emma Flannery.</span>
<span class="attribution"><span class="source">Photo: Kate Holden</span></span>
</figcaption>
</figure>
<p>Exactly when the megalodon became extinct remains a mystery, but several reasons are offered as to why it did – including, perhaps, that the food required to sustain such enormous creatures was running low during the <a href="https://en.wikipedia.org/wiki/Pliocene">Pliocene</a> epoch (5.33 million to 2.58 million years ago). With fierce competition from sharks such as great whites, the supposedly bigger female megalodons, in particular, may have been just too large for the oceans to sustain the needs of any more than a small population. The species, write the authors, “may have always lived on a knife edge”.</p>
<p>As we follow this toothy tale, we learn of the cult of collectors, some of whom will go to extraordinary lengths, diving to dangerous, pitch-dark depths, to acquire a much-prized tooth. </p>
<p>Megalodon teeth vary considerably in appearance because of the absorption of particular chemicals in rocks and sediment in the many locations where they have been found. The authors describe the beauty of some of the teeth they have seen – jewel-like, variously coloured and patterned – pointing readers towards some of the likeliest sites for successful fossil-hunting. The US east coast (especially North Carolina) is a particularly rich hunting ground.</p>
<p>However, they point out that hunting is not without its dangers. Amateur fossil excavation can also risk disturbing valuable sites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meg-2-the-truth-about-the-extinct-mega-shark-and-why-even-this-ridiculous-film-could-inspire-future-palaeontologists-210751">Meg 2: the truth about the extinct mega shark – and why even this ridiculous film could inspire future palaeontologists</a>
</strong>
</em>
</p>
<hr>
<h2>Truth in a tooth</h2>
<p>In the absence of a fully fossilised megalodon discovery that might reveal its shape and likely weight, it seems there is still a lot of truth in a tooth. The largest megalodon tooth yet found is “18cm from base to tip” and “almost certainly came from an individual that exceeded 15m in length”.</p>
<p>The shape of the tooth and its serrations confirm its job was to kill other marine mammals. The tooth’s marks on ancient bones or positions within them can reveal what the megalodon ate, while its colour, pattern and lustre can reveal the location of the creature when it died. </p>
<p>The authors acknowledge that the megalodon is not the ancestor of the great white shark – but analogies are made with this shark to allow the reader to get some sense of the kind of creature the megalodon might have been.</p>
<p>Two chapters, “Shark Eats Man” and “Man Eats Shark”, are almost entirely taken up with accounts of great white sharks, tiger sharks or bull sharks, either attacking humans, being attacked, or otherwise being used by humans to feed their desire for shark deities, shark trophies or shark fin soup. All of this rather distracts from the otherwise entertaining and informative story.</p>
<p>There is real passion in this story, but also horror and terror. Given the frequent analogies made with much oppressed, present-day sharks, more moderate language might have been used. The poor <a href="https://en.wikipedia.org/wiki/Greenland_shark">Greenland sharks</a> are gruesomely described. The great whites and others become the stuff of nightmares. Readers who will never experience the beauty of these elegant and inquisitive creatures in their own environments may well associate these sharks with the imagined meg, a “terrifying”, “horrifying” “monster”, with “razor-sharp teeth” that is the star of this book.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=471&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=471&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=471&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=592&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=592&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=592&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Man Eating Shark. Two chapters of the book focus on human-shark interactions.</span>
<span class="attribution"><span class="source">Sculpture and Photo: Dave Williams</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/friday-essay-the-meg-is-a-horror-story-but-our-treatment-of-sharks-is-scarier-100886">Friday essay: The Meg is a horror story but our treatment of sharks is scarier</a>
</strong>
</em>
</p>
<hr>
<p>In a final chapter, the authors return to the megalodon. Cryptozoologists, who search the planet for signs that creatures believed to be extinct are still alive, are on the trail of the megalodon following <a href="https://www.australiangeographic.com.au/topics/wildlife/2017/08/everything-you-need-to-know-about-the-megamouth-shark/">the discovery by a US navy ship in 1976 of a supposedly extinct megamouth shark</a>, a contemporary of the megalodon.</p>
<p>Tim and Emma doubt megalodons are still out there. The sharks would hunt, they reason, where they would be seen by us and there have been no traces of even parts of a megalodon washed ashore, as in the case of other large and mysterious creatures.</p>
<p>However, they’re optimistic that further scientific discoveries will reveal more about the true shape and size of the creature. </p>
<p>If a complete set of teeth could be found – exactly as they lay in the mouth – this would reveal how the jaws worked, how many teeth there were, and what megalodons primarily hunted. If enough of a fossil was found to indicate the length and shape of the fins, we might learn more about the megalodon’s swimming and hunting strategies.</p>
<p>In 1988, the fossil of an extinct cartilaginous shark (<em>Carcharodon hubbelli</em>) was <a href="https://www.foxnews.com/science/whos-your-daddy-great-white-sharks-parent-found">unearthed by an olive farmer</a> in the <a href="https://en.wikipedia.org/wiki/Pisco_Formation">Pisco Formation of Southern Peru</a>.</p>
<p>Tim Flannery suggests that if a megalodon fossil were to be found, it would most likely be in the Pisco Formation “where the ancient sea floor, miraculously preserved, is laid out in exquisite detail”.</p>
<p>For now, the creature, whose arrowhead tooth once sat in his youthful hand – pointing him to the path of palaeontology – exists largely in his imagination: the “megalodon in all its terrifying glory”.</p><img src="https://counter.theconversation.com/content/211506/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vivienne Westbrook has been the recipient of many international research funding institutes, though is not presently being funded by any organisation.</span></em></p>Megalodons are having a cultural moment. What do we know about them? And might further scientific discoveries reveal more about the true shape and size of these creatures?Vivienne Westbrook, Adjunct Senior Research Fellow, Oceans Institute, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2100842023-08-18T14:43:47Z2023-08-18T14:43:47ZWhy we think that some extinct giant flying reptiles cared for their young<figure><img src="https://images.theconversation.com/files/543063/original/file-20230816-28-82uhml.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C6082%2C2931&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pteranodon was a large-bodied pterosaur.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pteranodon-flying-genus-pterosaur-lived-during-2133739385">YuRi Photolife / Shutterstock</a></span></figcaption></figure><p>Our understanding of animal behaviour depends on observation. Researchers can study how animals are born, grow and develop. We can gather evidence of how they interact with each other and their environment.</p>
<p>But how do we do this for extinct animals? <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2023.1102">In a recent scientific paper</a>,
palaeontologist <a href="https://www.ucc.ie/en/mariamcnamara/whoweare/zixiao/">Zixiao Yang</a> and colleagues compared the growth of small and giant pterosaurs. </p>
<p>These were flying reptiles that were alive between about 228 million years ago and 66 million years ago – sharing the Earth with dinosaurs. Yang and colleagues wanted to understand what, if anything, was different about how the giant animals got so big.</p>
<figure class="align-center ">
<img alt="Pterosaur" src="https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Model pterosaur, Dimorphodon macronyx (reconstruction). Photographed at the National Museum of Scotland.</span>
<span class="attribution"><a class="source" href="https://www.jasongilchrist.co.uk/Blog_386348.html">Jason Gilchrist</a></span>
</figcaption>
</figure>
<p>They looked at the limb bones, which are critical to locomotion: the forelimbs to flight, the hindlimbs to movement on the ground. With the smaller-bodied pterosaurs (the smallest in the study had a wingspan of 0.19–0.74 metres), they discovered that the limb bones that lay closest to the body – the “proximal” ones – grew more slowly relative to their total body size as the animals aged after hatching.</p>
<p>For large-bodied pterosaur species, such as <a href="https://www.britannica.com/animal/Pteranodon"><em>Pteranodon</em></a>, with a wingspan range of 3.91-6.37 metres, the limb bones that lay closest to the body grew faster than other elements of their skeleton after hatching.</p>
<figure class="align-center ">
<img alt="Limb bone growth allometry in pterosaurs of different sizes. The wings of small-bodied pterosaurs show limb bones that grew slowly with respect to the rest of the body, indicating that they were potentially good fliers soon after hatching. Large-bodied pterosaur species, however, were born with relatively small arms. Even though their wing bones grew quickly after hatching relative to the rest of the body, the young of these species likely could not fly as efficiently and therefore parental care may have been required." src="https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=348&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=348&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=348&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=438&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=438&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=438&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Infographic showing different growth patterns in large and small pterosaurs.</span>
<span class="attribution"><span class="source">Yang Z, Jiang B, Benton MJ, Xu X, McNamara ME, Hone DWE.</span></span>
</figcaption>
</figure>
<p>In bird and mammal species alive today, this pattern is associated with particular developmental strategies. Present-day species showing a developmental pattern most similar to the smaller pterosaurs tend to <a href="https://web.stanford.edu/group/stanfordbirds/text/uessays/uPrecocial_and_Altricial.html">move around independently</a> from an early age.</p>
<p>While not necessarily lacking in parental care, such species tend to be less dependent on or demanding of their parents. By contrast, living species showing the developmental pattern seen in the larger <em>Pteranodon</em> tend to have young that are not capable of independent movement. In these animals, intensive parental care – including feeding the young – is the norm.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/dinosaur-egg-bonanza-gives-vital-clues-about-prehistoric-parenting-121401">Dinosaur egg bonanza gives vital clues about prehistoric parenting</a>
</strong>
</em>
</p>
<hr>
<h2>Wing development</h2>
<p>Using data from fossils, Yang and colleagues used computers to model the body measurements of different pterosaur species as they grew.</p>
<p><em>Pteranodon</em>‘s wing aspect ratio (the wing length relative to wing area) increased as the species grew, allowing it to develop a long, narrow wing, associated with soaring in modern birds. The smaller pterosaurs, however, showed a consistent or decreasing wing aspect ratio during growth, allowing more manoeuvrability.</p>
<p>These developmental differences between larger and smaller species of pterosaur indicate that <em>Pteranodon</em>’s relatively greater proximal limb growth shortly after hatching, along with – perhaps – enhanced parental care, may have helped it reach a large adult size. Pterosaurs as a group encompassed the largest flying animals of all time. <em><a href="https://link.springer.com/article/10.1007/s00114-002-0307-1">Hatzegopteryx thambema</a></em> may have been the biggest, with a wingspan of up to 12 metres. But all pterosaurs started small.</p>
<p>Pterosaur hatchlings’ size was limited by ultimately the size of their eggs, which was constrained by the size of the pelvic opening of female pterosaurs, and by the <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(14)00525-9">soft eggshell produced by pterosaurs</a>. Compared to hard-shelled bird eggs, soft eggs are weaker and cannot support larger sizes. To grow big, pterosaurs had to do most of their growing after they hatched.</p>
<h2>Parental care</h2>
<p>A key difference between the small and large species may have been parental care. This may have released large pterosaurs from growth and size constraints. An extended maturation period where parents protected their young and fed them may have allowed a bending of developmental physics, resulting in a larger body size, a lighter skeleton and more robust joints. In contrast, small pterosaur species by the nature of their slower proximal limb growth may have been locked into maturity at smaller sizes.</p>
<p>It’s also possible that baby pterosaurs from larger species with parental care were not capable of flight, whereas smaller species were <a href="https://www.nature.com/articles/s41598-021-92499-z">flight-ready upon hatching</a>.</p>
<p>To grow to such a large body size, the giant pterosaurs also needed two things from their environment: space and updrafts. Big pterosaurs would principally have been soarers, meaning that they used updrafts to stay aloft and economised on energy by minimising flapping. Giant pterosaurs also needed a food supply to support their large size and fuel their metabolic requirements.</p>
<p>While competitors for food were likely in short supply for large adult pterosaurs, youngsters – being smaller – would be more likely to overlap in terms of food sources and habitats with smaller pterosaur species. Young giant pterosaurs probably <a href="https://tetzoo.com/blog/2021/7/21/baby-pterosaurs-were-excellent-fliers-and-occupied-different-niches-from-their-parents">did not compete for food with adult pterosaurs of the same species</a>.</p>
<p>Predation on adult giant pterosaurs by other animals would have been limited. What dinosaurs (or other creatures) would have been big and hard enough to take on such an imposing sharp-beaked monster?</p>
<figure class="align-center ">
<img alt="Pteranodon longiceps being preyed on by a Cretoxyrhina shark." src="https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Large pterosaurs like Pteranodon probably had only a handful of predators, such as this large shark.</span>
<span class="attribution"><a class="source" href="https://www.markwitton.co.uk/">Mark Witton</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Future fossils</h2>
<p>Incredible as it seems, we can infer the presence of parental care – and lack thereof – in long-dead species of flying reptile. The odds of a pterosaur being preserved in the act of unambiguous parental care seem incredibly slim. So evidence from fossils and understanding patterns from contemporary species are critical to our understanding.</p>
<p>At some point, someone will hopefully find juvenile giant pterosaurs, and their hatchlings, eggs and embryos. Otherwise, questions will remain regarding the development of baby pterosaurs.</p>
<p>These questions include: what was the nature of the parental care? Did parents keep eggs and young warm by sitting over them? Did they defend juveniles against predators, providing food for pterosaur babies? Did males and females share parental care equally? Did they care for young that were not their own?</p>
<p>To more fully re-imagine the early lives and parental behaviour of giant pterosaurs, we need more fossils. Let’s find them.</p><img src="https://counter.theconversation.com/content/210084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Gilchrist does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Reptiles don’t generally care for their offspring, but some pterosaurs may have bucked the trend.Jason Gilchrist, Lecturer in the School of Applied Sciences, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2117122023-08-17T19:42:11Z2023-08-17T19:42:11ZA changing climate, growing human populations and widespread fires contributed to the last major extinction event − can we prevent another?<p>Over the past decade, deadly wildfires have become increasingly common because of both <a href="https://www.scientificamerican.com/article/climate-change-is-escalating-californias-wildfires/">human-caused climate change</a> and <a href="https://www.nytimes.com/2023/08/13/us/hawaii-wildfire-factors.html">disruptive land management practices</a>. Southern California, where the three of us live and work, has been <a href="https://ktla.com/news/the-cities-where-wildfires-threaten-the-most-homes-in-california/">hit especially hard</a>.</p>
<p>Southern California also experienced a wave of wildfires 13,000 years ago. These fires permanently transformed the region’s vegetation and <a href="https://www.science.org/doi/10.1126/science.abo3594">contributed to Earth’s largest extinction</a> in more than 60 million years.</p>
<p>As <a href="https://www.ioes.ucla.edu/person/emily-lindsey/">paleontologists</a>, <a href="https://nhm.org/person/dunn-regan">we have</a> a <a href="https://scholar.google.com/citations?user=_FveDz4AAAAJ&hl=en">unique perspective</a> on the long-term causes and consequences of environmental changes, both those linked to natural climate fluctuations and those wrought by humans. </p>
<p><a href="https://www.science.org/doi/10.1126/science.abo3594">In a new study</a>, published in August 2023, we sought to understand changes that were happening in California during the last major extinction event at the <a href="https://www.britannica.com/science/Pleistocene-Epoch">end of the Pleistocene</a>, a time period known as the Ice Age. This event wiped out <a href="https://www.smithsonianmag.com/science-nature/what-happened-worlds-most-enormous-animals-180964255/">most of Earth’s large mammals</a> between about 10,000 and 50,000 years ago. This was a time marked by dramatic climate upheavals and rapidly spreading human populations. </p>
<h2>The last major extinction</h2>
<p>Scientists often call the past 66 million years of Earth’s history the Age of Mammals. During this time, our furry relatives took advantage of the <a href="https://www.nhm.ac.uk/discover/how-an-asteroid-caused-extinction-of-dinosaurs.html">extinction of the dinosaurs</a> to become the dominant animals on the planet. </p>
<p>During the Pleistocene, Eurasia and the Americas teemed with enormous beasts like woolly mammoths, giant bears and dire wolves. Two species of camels, three species of ground sloths and five species of large cats <a href="https://tarpits.org/research-collections/tar-pits-collections/mammal-collections">roamed what is now Los Angeles</a>.</p>
<p>Then, abruptly, they were gone. All over the world, the large mammals that had characterized global ecosystems for tens of millions of years disappeared. North America <a href="https://www.doi.org/10.1146/annurev.ecolsys.34.011802.132415">lost more than 70%</a> of mammals weighing more than 97 pounds (44 kilograms). South America lost more than 80%, Australia nearly 90%. Only Africa, Antarctica and a few remote islands retain what could be considered “natural” animal communities today.</p>
<p>The reason for these extinctions remains obscure. For decades, paleontologists and archaeologists have debated potential causes. What has befuddled scientists is not that there are no obvious culprits but that there are too many. </p>
<p>As the last ice age ended, a warming climate led to altered weather patterns and the reorganization of <a href="https://doi.org/10.1016/j.quascirev.2015.08.029">plant communities</a>. At the same time, human populations were rapidly increasing and <a href="https://www.worldhistory.org/article/1070/early-human-migration/">spreading around the globe</a>. </p>
<p>Either or both of these processes could be implicated in the extinction event. But the fossil record of any region is usually too sparse to know exactly when large mammal species disappeared from different regions. This makes it difficult to determine whether habitat loss, resource scarcity, natural disasters, human hunting or some combination of these factors is to blame.</p>
<h2>A deadly combination</h2>
<p>Some records offer clues. <a href="https://tarpits.org/">La Brea Tar Pits</a> in Los Angeles, the world’s richest ice age fossil site, preserves the bones of thousands of large mammals that were trapped in viscous asphalt seeps <a href="https://resolver.caltech.edu/CaltechAUTHORS:20191203-160736818">over the past 60,000 years</a>. Proteins in these bones can be precisely dated <a href="https://doi.org/10.1016/j.quageo.2014.03.002">using radioactive carbon</a>, giving scientists unprecedented insight into an ancient ecosystem and an opportunity to illuminate the timing – and causes – of its collapse. </p>
<p>Our recent study from La Brea Tar Pits and <a href="https://en.wikipedia.org/wiki/Lake_Elsinore">nearby Lake Elsinore</a> has unearthed evidence of a dramatic event 13,000 years ago that permanently transformed Southern California’s vegetation and <a href="https://www.science.org/doi/10.1126/science.abo3594">caused the disappearance</a> of La Brea’s iconic mega-mammals. </p>
<p>Sediment archives from the lake’s bottom and archaeological records provide evidence of a deadly combination – a warming climate <a href="https://doi.org/10.1002/jqs.3018">punctuated by decadeslong droughts</a> and rapidly rising human populations. These factors pushed the Southern California ecosystem to a tipping point. </p>
<p><a href="https://www.doi.org/10.1126/sciadv.1501682">Similar combinations</a> of climate warming and human impacts have been blamed for ice age extinctions elsewhere, but our study found something new. The catalyst for this dramatic transformation seems to have been an unprecedented increase in wildfires, which were probably set by humans. </p>
<p>The processes that led to this collapse are familiar today. As California warmed coming out of the last ice age, the landscape became drier and forests receded. At La Brea, herbivore populations declined, probably from a combination of human hunting and habitat loss. Species associated with trees, like camels, disappeared entirely. </p>
<p>In the millennium leading up to the extinction, mean annual temperatures in the region <a href="https://doi.org/10.1016/j.epsl.2019.03.024">rose 10 degrees Farenheit</a> (5.5 degrees Celsius), and the lake began evaporating. Then, 13,200 years ago, the ecosystem entered a 200-year-long drought. Half of the remaining trees died. With fewer large herbivores to eat it, dead vegetation built up on the landscape. </p>
<p>At the same time, human populations began expanding across North America. And as they spread, people brought with them a powerful new tool – fire. </p>
<p>Humans and our ancestors have used fire for <a href="https://www.science.org/content/article/artificial-intelligence-may-have-unearthed-one-world-s-oldest-campfires">hundreds of thousands of years</a>, but fire has <a href="https://www.firescience.gov/projects/09-2-01-9/supdocs/09-2-01-9_Chapter_3_Fire_Regimes.pdf">different impacts in different ecosystems</a>. Charcoal records from Lake Elsinore reveal that before humans, fire activity was low in coastal Southern California. But 13,200 to 13,000 years ago, as human populations grew, fire in the region increased by an order of magnitude. </p>
<p>Our research suggests that the combination of heat, drought, herbivore loss and human-set fires had pushed this system to a <a href="https://www.nature.com/articles/nature11018">tipping point</a>. At the end of this period, Southern California was covered in chaparral plants, which thrive after fires. A new fire regime had become established, and the iconic La Brea megafauna had disappeared.</p>
<h2>Lessons for the future</h2>
<p>Studying the causes and consequences of the Pleistocene extinctions in California can provide valuable context for understanding today’s climate and biodiversity crises. A similar combination of climate warming, expanding human populations, biodiversity loss and human-ignited fires that characterized the ice age extinction interval in Southern California are <a href="https://www.doi.org/10.1126/science.abb0355">playing out again today</a>.</p>
<p>The alarming difference is that temperatures today are rising <a href="https://www.scientificamerican.com/article/todays-climate-change-proves-much-faster-than-changes-in-past-65-million-years/">10 times faster</a> than they did at the end of the ice age, primarily because of the burning of fossil fuels. This human-caused climate change has contributed to a fivefold increase in fire frequency and intensity and the amount of area burned in the state of California in the <a href="https://doi.org/10.1029/2019EF001210">past 45 years</a>. </p>
<p>While California is now <a href="https://earthobservatory.nasa.gov/images/148908/whats-behind-californias-surge-of-large-fires">famous for extreme fires</a>, our study reveals that fire is a relatively new phenomenon in this region. In the 20,000 years leading up to the extinction, the Lake Elsinore record shows very low incidence of any fire even during comparable periods of drought. Only after human arrival does fire become a regular part of the ecosystem. </p>
<p>Even today, <a href="https://www.businessinsider.com/pge-caused-california-wildfires-safety-measures-2019-10">downed power lines</a>, campfires and <a href="https://www.nytimes.com/2020/09/07/us/gender-reveal-party-wildfire.html">other human activities</a> start <a href="https://doi.org/10.1071/WF18026">over 90%</a> of wildfires in coastal California. </p>
<p>The parallels between the late Pleistocene megafaunal extinctions and today’s environmental crises are striking. The past teaches us that the ecosystems we depend upon are vulnerable to collapse when stressed by multiple intersecting pressures. Redoubling efforts to eliminate greenhouse gas emissions, prevent reckless fire ignitions and preserve Earth’s remaining megafauna can help avert another, even more catastrophic transformation.</p><img src="https://counter.theconversation.com/content/211712/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emily Lindsey receives funding from the National Science Foundation, which funded some of the research reported in this article. </span></em></p><p class="fine-print"><em><span>Lisa N. Martinez receives funding from the National Science Foundation and the UCLA Endowed Chair in Geography of California and the American West. </span></em></p><p class="fine-print"><em><span>Regan E. Dunn receives funding from National Science Foundation and NASA. </span></em></p>New findings from the La Brea Tar Pits in southern California suggest human-caused wildfires in the region, along with a warming climate, led to the loss of most of the area’s large mammals.Emily Lindsey, Associate Curator, La Brea Tar Pits; Adjunct Faculty, Institute of the Environment and Sustainability, UCLA, University of California, Los AngelesLisa N. Martinez, Ph.D. Candidate in Geography, University of California, Los AngelesRegan E. Dunn, Adjunct Professor of Earth Sciences, USC Dornsife College of Letters, Arts and SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2101102023-07-20T14:45:19Z2023-07-20T14:45:19ZThirty years after Jurassic Park hit movie screens, its impact on science and culture remains as strong as ever – podcast<figure><img src="https://images.theconversation.com/files/538375/original/file-20230719-22038-i0v8x9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5351%2C3564&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Jurassic Park franchise has spawned several movies, theme parks and spin-off products.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p><em>Jurassic Park</em>, the 1993 film about dinosaurs, is a cultural tour de force. Not only did the film herald a new era in computer-generated movie effects, it also revived the field of paleontology. And if that wasn’t enough, it raised questions about the ethics of DNA research.</p>
<p>Based on Michael Crichton’s novel by the same name, <em>Jurassic Park</em> told the story of an ambitious theme park that used resurrected dinosaurs as its attractions. But as the story unfolds, things start to go wrong.</p>
<iframe src="https://embed.acast.com/60087127b9687759d637bade/64b93712c23a750011163e18" frameborder="0" width="100%" height="190px"></iframe>
<p><iframe id="tc-infographic-561" class="tc-infographic" height="100" src="https://cdn.theconversation.com/infographics/561/4fbbd099d631750693d02bac632430b71b37cd5f/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>In this Discovery episode of <em>The Conversation Weekly</em>, we speak with Travis Holland, a senior lecturer at Charles Sturt University in Australia. He researches media and fan studies, and has looked at the popular and scientific cultural impact <em>Jurassic Park</em> continues to have.</p>
<p>“We started to see through the mid part of the 1900s a dinosaur renaissance, where there was a spate of interesting research discoveries happening all around the world,” Holland said. “Jurassic Park came at the tail end of that. It took all of this new science and made it public.”</p>
<h2>Philosophical questions</h2>
<p>The film’s plot is based on the ability of scientists to produce animals from DNA and resurrect prehistoric animals using that technology. Since 1993, DNA science has developed so much that this premise is no longer a far-fetched science fiction plot.</p>
<p>The film — and its science — have influenced and shaped research not only in paleontology, but also in genetic technologies. In a somewhat prescient move related to genetic science, Dolly the sheep, the first cloned mammal, <a href="https://www.theguardian.com/science/2022/jun/21/life-will-find-a-way-could-scientists-make-jurassic-park-a-reality">was born three years after <em>Jurassic Park</em> was released</a>.</p>
<p>In a highly publicized announcement, the biotech company <a href="https://colossal.com/mammoth/">Colossal Biosciences is trying to bring back the woolly mammoth</a> and other extinct species.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2Sjf5kvSOd0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Texas-based company Colossal Biosciences is trying to resurrect extinct species.</span></figcaption>
</figure>
<p><em>Jurassic Park</em> posed the question to viewers that even if the science to resurrect extinct species did exist, should it be used? The film doesn’t resolve this question, and it’s one that has grown in importance as genetic technologies are becoming more sophisticated and mainstream.</p>
<h2>Representation and art</h2>
<p>Holland’s work considers <em>Jurassic Park</em> within a lineage of dinosaur representations and depictions — what he refers to as paleo-media. These representations of dinosaurs were a combination of thorough paleontological research and art.</p>
<p>“Charles R. Knight painted a mural called the Leaping Laelaps, which is these two therapod dinosaurs leaping at each other,” Holland says. “I’d suggest that that piece of art possibly inspired even the Velociraptors and the way they leaped in Jurassic Park.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an illustration of two light green dinosaurs jumping in a meadow" src="https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538385/original/file-20230719-27-tivq2y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">CAPTION.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Laelaps-Charles_Knight-1897.jpg">(Charles R. Knight/Wikimedia Commons)</a></span>
</figcaption>
</figure>
<p>Since 1993, there have been a total of six <em>Jurassic Park</em> films released in the franchise, with the most recent one coming out last year. To hear how the film continues to inspire new generations of scientists, artists and filmmakers, tune in to this Discovery episode of <em>The Conversation Weekly</em>.</p>
<hr>
<p>This episode was written and produced by Katie Flood and hosted by Nehal El-Hadi. Mend Mariwany is the executive producer of The Conversation Weekly. Eloise Stevens does our sound design, and our theme music is by Neeta Sarl.</p>
<p>You can find us on Twitter <a href="https://twitter.com/TC_Audio">@TC_Audio</a>, on Instagram at <a href="https://www.instagram.com/theconversationdotcom/">theconversationdotcom</a> or <a href="mailto:podcast@theconversation.com">via email</a>. You can also sign up to The Conversation’s <a href="https://theconversation.com/newsletter">free daily email here</a>. A transcript of this episode will be available soon.</p>
<p>Listen to <em>The Conversation Weekly</em>_ via any of the apps listed above, download it directly via our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a> or find out <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">how else to listen here</a>.</p><img src="https://counter.theconversation.com/content/210110/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nehal El-Hadi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Jurassic Park was a technological breakthrough for film because of its use of CGI. It also revived an interest in paleontology and raised ethical questions about DNA use.Nehal El-Hadi, Science + Technology Editor & Co-Host of The Conversation Weekly Podcast, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2064922023-05-30T23:01:55Z2023-05-30T23:01:55ZNewly described enormous marsupial wandered great distances across Australia 3.5 million years ago<figure><img src="https://images.theconversation.com/files/529010/original/file-20230530-25-p0dr9l.JPG?ixlib=rb-1.1.0&rect=440%2C579%2C2160%2C1342&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Jacob van Zoelen</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Today, 80% of Australia is arid, but it was not always that way. In the early Pliocene, 5.4 to 3.6 million years ago, Australia had a greenhouse climate, widespread forests and diverse marsupial animals.</p>
<p>As the climate dried out in the late Pliocene, open woodland, grassland and shrubland spread across Australia. How did large marsupials cope with these changes?</p>
<p>In 2017, Flinders University researchers uncovered a skeleton eroding from a cliff face on the Warburton River, at the Australian Wildlife Conservancy’s Kalamurina Station in northern South Australia.</p>
<p>The skeleton belongs to a species in the family <a href="https://en.wikipedia.org/wiki/Diprotodontidae">Diprotodontidae</a> – a group of four-legged herbivores that were the largest marsupials to ever exist. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of a rust coloured rock face and a map of Australia above it" src="https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1005&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1005&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1005&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1263&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1263&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528789/original/file-20230529-29-wug34x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1263&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of fossil deposits where the species was found (A & B). Close up of the Main Body of the Tirari Formation as exposed at Keekalanna East with some elements in situ (C).</span>
<span class="attribution"><span class="source">Aaron Camens</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In a new study <a href="https://dx.doi.org/10.1098/rsos.230211">published in Royal Society Open Science today</a>, we describe this fossil finding in detail, providing new insights into how the animal lived and moved.</p>
<h2>Exceptional preservation</h2>
<p>Wombats are the closest living relatives of diprotodontids, but the two are as distantly related as kangaroos are to possums. As a result, palaeontologists have had a hard time reconstructing these large, long-gone animals, especially since most diprotodontid species have been described mainly from jaws and teeth.</p>
<p>But the common, widespread nature of diprotodontid remains indicates they were an integral part of Australian ecosystems until the last species, including the rhino-sized <em>Diprotodon optatum</em>, became extinct about 40,000 years ago. </p>
<p>It is rare to find multiple bones belonging to a single skeleton in the fossil record. Only a handful of studies have described parts of the limbs of a post-Miocene diprotodontid. As such, the newly described skeleton is of great importance and is even more special, as it is the first to be found with associated soft tissue structures. </p>
<p>We also compared the specimen to more than 2,000 diprotodontid elements from museums across the globe, making this the most comprehensive appraisal of a diprotodontid skeleton to date.</p>
<p>Our comparisons revealed the skeleton belongs to a new genus we named <em>Ambulator</em>, meaning walker or wanderer. We chose this name because the locomotory adaptations of the legs and feet of this quarter-tonne animal would have made it well suited to roaming long distances in search of food and water, especially when compared to earlier relatives.</p>
<p>We 3D-scanned the specimen, and the files are freely available for anyone <a href="https://www.morphosource.org/projects/000497863?locale=en">to download and look at online</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black silhouette of a rhino like animal with bones overlaid in several places" src="https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=327&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=327&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=327&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=411&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=411&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529005/original/file-20230530-23-d5un5v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=411&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Reassembled partial skeleton of <em>Ambulator keanei</em>, with a silhouette demonstrating advanced adaptations for its style of walking.</span>
<span class="attribution"><span class="source">Jacob van Zoelen</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/giant-marsupials-once-migrated-across-an-australian-ice-age-landscape-84762">Giant marsupials once migrated across an Australian Ice Age landscape</a>
</strong>
</em>
</p>
<hr>
<h2>Walking marsupials</h2>
<p>We don’t often think of walking as a special skill – but when you’re big, any movement can be energetically costly, so efficiency is key. </p>
<p>Most large herbivores today, such as elephants and rhinoceroses, are unguligrade, meaning they walk on the tips of their toes, with their wrists or ankles not touching the ground.</p>
<p>Diprotodontids are what we call <a href="https://www.britannica.com/animal/mammal/Locomotion#ref193762">plantigrade</a>, meaning their heel-bone contacts the ground when they walk – similar to human feet. This stance helps distribute weight and reduces energy loss when walking, but uses more energy for other activities such as running.</p>
<p>Many diprotodontids also have so-called extreme plantigrady in their hands – a wrist bone modified into a secondary heel. This “heeled hand” made early reconstructions of these animals look bizarre and awkward.</p>
<p>Development of the wrist and ankle for weight-bearing meant the digits became essentially functionless and likely did not make contact with the ground while walking. This may be why no finger or toe impressions are observed in the trackways of diprotodontids.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&rect=38%2C72%2C2517%2C1716&q=45&auto=format&w=1000&fit=clip"><img alt="A grey rock with shallow, oddly shaped footprints" src="https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&rect=38%2C72%2C2517%2C1716&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528986/original/file-20230530-24-a8jbqg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hand and foot impression of <em>Diprotodon optatum</em> – with no sign of digits.</span>
<span class="attribution"><span class="source">Aaron Camens</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Climbers, walkers and grabbers</h2>
<p>Diprotodontids have limb-bone shapes that can be grouped into three main types. There are those adapted to tree climbing, such as <a href="https://theconversation.com/fossils-reveal-australias-tree-top-heavyweight-herbivore-10888"><em>Nimbadon lavarackorum</em></a> and <em>Ngapakaldia tedfordi</em>; and those adapted to more efficient locomotion and travelling great distances, such as <em>Diprotodon optatum</em> and <em>Ambulator keanei</em> (we call these “walkers”).</p>
<p>There are also diprotodontids that were terrestrial and probably could not climb. However, unlike the walkers, their forelimbs were not as specialised for walking and were able to perform a range of functions. These were “grabbers” such as <em>Neohelos stirtoni</em>, and likely <em>Kolopsis torus</em> and <em>Plaisiodon centralis</em>.</p>
<p>Walkers do not show up in the fossil record until we get to the Pliocene (3.5 million years ago). In fact, <em>A. keanei</em> is the earliest diprotodontid we know of that had these specialised walking adaptations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart showing skeleton bones in three orientations" src="https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529022/original/file-20230530-25-d332p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comparisons of the left hand of three diprotodontids. From left to right a composite hand of: 8 million-year-old Alcoota diprotodontid, a grabber; 3.5 million-year-old <em>A. keanei</em>, a walker; and 50 thousand-year-old <em>Diprotodon optatum</em>, also a walker.</span>
<span class="attribution"><span class="source">Jacob van Zoelen</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>During the Pliocene, when <em>A. keanei</em> was around, there was an increase in grasslands and open habitat as Australia became drier. Diprotodontids likely had to travel much greater distances to obtain enough water and their preferred food, which was the soft leaves of shrubs and trees, not grass.</p>
<p>Animals such as <em>Ambulator</em> may have evolved to traverse great distances more efficiently. This may also have allowed diprotodontids to get bigger and support more weight. This would eventually lead to the evolution of the giant and <a href="https://australian.museum/learn/australia-over-time/extinct-animals/diprotodon-optatum/">relatively well-known 2.7 tonne <em>Diprotodon</em></a>. </p>
<p>Unfortunately, we will never get to see great migrating mobs of diprotodontids. But it’s amazing to know such a thing may have once been commonplace across the continent.</p><img src="https://counter.theconversation.com/content/206492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacob van Zoelen received funding from by the Australian Government Research Training Program Scholarship (Excellence). Travel to collections was partially funded by the Royal Society of South Australia small grant scheme 2018, the University of California Museum of Paleontology Doris O. and Samuel P. Welles Fund 2019, Flinders University Higher Degree Research International Conference Travel Grant 2019 and the North American Paleontology Conference Student Travel Grant.</span></em></p><p class="fine-print"><em><span>Gavin Prideaux receives funding from the Australian Research Council, Australia Pacific Science Foundation, Hermon Slade Foundation, Australian Geographic and National Geographic.</span></em></p><p class="fine-print"><em><span>Aaron Camens does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Having special foot adaptations helped these sizeable animals wander long distances, which meant a better chance to find plentiful food and water.Jacob van Zoelen, PhD Candidate, Flinders UniversityAaron Camens, Lecturer in Palaeontology, Flinders UniversityGavin Prideaux, Professor, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2065012023-05-30T14:02:40Z2023-05-30T14:02:40ZThese magnificent 107-million-year-old pterosaur bones are the oldest ever found in Australia<p>New research on old bones has shed light on pterosaur fossils from the early Cretaceous period of Australia, which took place roughly 107 million years ago.</p>
<p>The bones were discovered in Victoria in the late 1980s at a fossil site called <a href="https://museumsvictoria.com.au/article/the-700/">Dinosaur Cove</a>, a few hours’ drive west of Melbourne.</p>
<p>Our paper describing the bones is <a href="https://tandfonline.com/doi/full/10.1080/08912963.2023.2201827">published today in Historical Biology</a>.</p>
<h2>The oldest pterosaur bones we have</h2>
<p>The Dinosaur Cove fossils are the geologically oldest pterosaur remains we have from the <a href="https://www.britannica.com/science/Cretaceous-Period/Major-subdivisions-of-the-Cretaceous-System">Lower Cretaceous</a> of Australia. </p>
<p>These bones belonged to two separate individuals, because there’s a relative size difference between the two.</p>
<p>One specimen is a partial sacrum (the fused vertebrae from between the pelvic bones), a relative rarity in the pterosaur fossil record. The other is a comparatively small fourth metacarpal (part of the wing finger) – it is the first evidence of a juvenile pterosaur found in Australia.</p>
<p>Although we couldn’t pinpoint exactly which species in the pterosaur family these bones came from, the partial sacrum belonged to an individual with a wingspan estimated to exceed two metres. By contrast, the juvenile pterosaur had a wingspan just over one metre. </p>
<figure class="align-center ">
<img alt="Silhouettes of a woman compared with Australian Cretaceous pterosaurs" src="https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=299&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=299&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=299&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528526/original/file-20230526-21-5fzgqw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wingspan estimates of Australian pterosaurs, including <em>Ferrodraco lentoni</em>, an adult from the Upper Cretaceous of Queensland, compared with the newly described Victorian pterosaurs from the Lower Cretaceous.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>In the early Cretaceous, approximately 110–107 million years ago, Victoria was virtually unrecognisable. The Bass Strait was a narrow valley occupied by fast-flowing rivers. Conifers and ginkgoes grew here instead of eucalypts and grasses, and dinosaurs reigned.</p>
<p>On the ground, the dominant herbivore animals were <a href="https://theconversation.com/meet-the-diverse-group-of-plant-eating-dinosaurs-that-roamed-victoria-110-million-years-ago-166343">small-bodied, beaked ornithopods</a>, perpetually wary of the <a href="https://www.swinburne.edu.au/news/2019/10/huge-clawed-predatory-dinosaur-discovery-in-victoria/">rapacious megaraptoran theropods</a>.</p>
<p>For more than 30 years, it has been clear to scientists that flying reptiles called pterosaurs soared through the Victorian Cretaceous skies, above the heads of the dinosaurs. Until recently, however, they have remained a mystery.</p>
<h2>Treasure at Dinosaur Cove</h2>
<p>Large-scale excavations at <a href="https://depositsmag.com/2020/07/02/hell-and-high-water-the-digs-of-dinosaur-cove/">Dinosaur Cove</a> began in 1984, and for more than 40 years, a team of volunteers called <a href="http://dinosaurdreaming.monash.edu/">Dinosaur Dreaming</a> have excavated fossil sites along several other sites scattered across the Victorian coast.</p>
<p><a href="https://museumsvictoria.com.au/about-us/staff/dr-thomas-rich/">Tom Rich</a> and <a href="https://research.monash.edu/en/persons/patricia-rich">Pat Vickers-Rich</a>, co-authors of our newly published paper, led the excavations that yielded not just the newly described pterosaurs, but myriad other discoveries as well. </p>
<figure class="align-center ">
<img alt="Two palaeontologists holding pterosaur bones" src="https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528532/original/file-20230526-27-8vpr49.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Co-authors Pat Vickers-Rich and Tom Rich holding the pterosaur specimens we described.</span>
<span class="attribution"><span class="source">Tim Ziegler, Author provided</span></span>
</figcaption>
</figure>
<p>The work at this rich fossil site has resulted in thousands of dinosaur bones and other fossils. These include fossil fish (bony fish and lungfish), skeletal remains from ornithopods, megaraptoran theropods, aquatic plesiosaurs and prehistoric mammals. There was also <a href="https://ecoevocommunity.nature.com/posts/a-tiny-dinosaur-bone-with-a-big-story-to-tell-australia-s-first-elaphrosaur">Australia’s only elaphrosaurine theropod</a>: a lightly-built dinosaur with a small head, long neck, relatively short front limbs, long hind limbs and a long tail.</p>
<p>But among the rarest vertebrate fossils from Dinosaur Cove are those from pterosaurs.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meet-the-diverse-group-of-plant-eating-dinosaurs-that-roamed-victoria-110-million-years-ago-166343">Meet the diverse group of plant-eating dinosaurs that roamed Victoria 110 million years ago</a>
</strong>
</em>
</p>
<hr>
<h2>Australia’s pterosaur record</h2>
<p>The majority of Australia’s pterosaur fossils have been found in central-western Queensland. Indeed, <a href="https://www.nature.com/articles/288361a0">the first pterosaurs reported from the continent</a> were isolated remains from the Eromanga Basin, described in 1980.</p>
<p>Since then, more pterosaur material has come to light, with four Australian pterosaur species currently recognised: <a href="https://www.sciencedirect.com/science/article/pii/S0195667118302775"><em>Mythunga camara</em></a>, <a href="https://www.scielo.br/j/aabc/a/cbd3DSy74yzYnnrTvfqw73M/?format=pdf&lang=en"><em>Aussiedraco molnari</em></a>, <a href="https://www.nature.com/articles/s41598-019-49789-4"><em>Ferrodraco lentoni</em></a> and <a href="https://www.tandfonline.com/doi/abs/10.1080/02724634.2021.1946068"><em>Thapunngaka shawi</em></a>.</p>
<p><em>Ferrodraco</em> is the most complete Australian pterosaur to date, and is represented by <a href="https://www.tandfonline.com/doi/full/10.1080/02724634.2021.2038182">an adult individual with a wingspan of approximately four metres</a>, which we named as a new species in 2019.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/4-metre-flying-reptile-unearthed-in-queensland-is-our-best-pterosaur-fossil-yet-124581">4-metre flying reptile unearthed in Queensland is our best pterosaur fossil yet</a>
</strong>
</em>
</p>
<hr>
<p>Other pterosaur fossils from Australia include isolated remains from the Cretaceous of Western Australia, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5419211/">opalised pterosaur teeth</a> from the mid-Cretaceous of Lightning Ridge in New South Wales.</p>
<figure class="align-right ">
<img alt="Three pterosaur wing bones" src="https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/528531/original/file-20230526-17-nzdm20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Three pterosaur wing bones from three individuals. Left: right metacarpal from the Toolebuc Formation was discovered at Slashers Creek Station, east of Boulia, Queensland. Middle: Left metacarpal from <em>Ferrodraco lentoni</em> from the Winton Formation, discovered northeast of Winton, Queensland. Right: a left metacarpal from a juvenile pterosaur from Dinosaur Cove, Victoria.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>We don’t know which species the Victorian pterosaurs belong to. However, the comparatively small fourth metacarpal – a bone from the wing – is the first unequivocal evidence of a juvenile pterosaur from Australia. </p>
<h2>Pterosaurs at high latitudes</h2>
<p>Few pterosaur remains have been reported from fossil sites that were at high latitudes during the Age of Reptiles – the Mesozoic Era.</p>
<p>Antarctica, which was at high latitudes throughout, <a href="https://www.scielo.br/j/aabc/a/CcYBLYkgDhfJfvQDNdRxK4m/?lang=en">has produced three pterosaur fossils</a>. One of these awaits formal description, and another was <a href="https://theconversation.com/lesson-from-brazil-museums-are-not-forever-102692">recovered from the charred remains of the National Museum of Brazil</a>.</p>
<p>The only reports of high-latitude pterosaurs in the northern hemisphere are of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/let.12006?casa_token=zOdjm4--NfkAAAAA%3A8_IIW_UhaReQVG1aohnc24Sl5BFtEqdWlYm4jEN_b-OTM5Ghdd_umZyigE1Y8gaxkMwwKnie0eSML8pt">isolated footprints</a>.</p>
<p>During the Cretaceous, <a href="https://www.geologypage.com/wp-content/uploads/2014/04/CretaceousPeriod.jpg">Australia was farther south than it is today</a>. In fact, Victoria was within the polar circle during much of the Cretaceous. Southeast Australia was not frozen over at this time, but there were weeks or months of continuous darkness during the winter. Despite these <a href="https://www.amazon.com/Dinosaurs-Darkness-Second-Search-Polar/dp/0253029406">harsh polar conditions</a>, life found a way to survive and thrive. </p>
<p>This prompts a few questions: were pterosaurs permanent residents in southeast Australia? Or did they migrate south during summer and head north for the winter?</p>
<p><a href="https://www.nature.com/articles/s41598-021-92499-z">From a young age, pterosaurs were adept fliers</a>, their bones already able to withstand the stresses of both launch and flight. However, subtle variations in the shape of the bones imply that hatchlings differed from their adult counterparts in terms of speed and manoeuvrability. </p>
<p>Until we discover pterosaur eggs or embryonic individuals at sites that were at high latitudes at the time, we won’t be able to confirm if pterosaurs were year-round residents or migratory.</p>
<p>Despite the rarity of pterosaurs in the fossil record, it is only a matter of time before we find more complete pterosaur material from Dinosaur Cove and other Cretaceous sites from coastal Victoria. Then, we can finally uncover the identity of these ancient, enigmatic winged reptiles.</p><img src="https://counter.theconversation.com/content/206501/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adele Pentland receives funding from the Australian Government Research Training Program Stipend.</span></em></p><p class="fine-print"><em><span>Stephen Poropat does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In the dinosaur era, flying reptiles soared in the skies of what is now Australia – but we have barely any fossil records of them.Adele Pentland, PhD candidate, Curtin UniversityStephen Poropat, Research associate, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1971852023-02-06T13:29:10Z2023-02-06T13:29:10ZHow did birds survive while dinosaurs went extinct?<figure><img src="https://images.theconversation.com/files/505982/original/file-20230123-25-t7bakx.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6000%2C3000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It wasn't flying that gave birds the advantage.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/miragaia-dinosaur-bellows-in-protest-as-royalty-free-illustration/495835013">Corey Ford/Stocktrek Images via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>If dinosaurs died, how come there are birds? Caiden S., age 9, Wylie, Texas</strong></p>
</blockquote>
<hr>
<p>Everyone knows what a bird is – and pretty much everyone knows what a dinosaur is. But not everyone is aware that <a href="https://doi.org/10.1371/journal.pone.0039056">birds evolved from dinosaurs</a> approximately 160 million years ago. </p>
<p>In fact, birds and dinosaurs lived together for about 100 million years. Birds descended from a particular group of dinosaurs called the dromaeosaurs, or “running lizards,” which were a family of feathered theropod or “beast foot” dinosaurs that included velociraptor. </p>
<p>But when an <a href="https://doi.org/10.1126/science.1177265">asteroid struck Earth 66 million years ago</a> off the coast of what is now Mexico, <a href="https://theconversation.com/scientists-have-found-dust-from-the-asteroid-that-wiped-out-the-dinosaurs-inside-the-crater-it-left-156232">dinosaurs went extinct</a> – but some birds remained. You might wonder why. </p>
<p>By acting like detectives, scientists who specialize in bird evolution are trying to figure out why birds weren’t wiped out too. They piece together clues like fossils and other evidence about life on Earth long ago. For now, scientists have ideas about why birds survived, but no firm answers.</p>
<h2>Perks of being toothless</h2>
<p>Today’s <a href="https://www.allaboutbirds.org/news/do-birds-have-teeth/">birds have no teeth</a>. Instead they have beaks or bills, which come in many shapes and sizes for eating and drinking. But some of the <a href="http://dx.doi.org/10.1016/j.cub.2016.03.039">birds that lived in dinosaur times actually had teeth</a>. Others did not. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="In the foreground is an artist's rendering of a bird head. In the background is a fossil photo showing that bird's skull. Teeth are clearly seen in the jaws." src="https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=515&fit=crop&dpr=1 600w, https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=515&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=515&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=647&fit=crop&dpr=1 754w, https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=647&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/503346/original/file-20230105-24-d58wgt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=647&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Ichthyornis dispar</em> was a primitive seabird with teeth that lived during the late Cretaceous Period – from 100 million to 66 million years ago – in North America.</span>
<span class="attribution"><span class="source">Courtesy of Michael Hanson and Bhart-Anjan S. Bhullar.</span></span>
</figcaption>
</figure>
<p>After the asteroid struck Earth long ago, all birds with teeth went extinct. But many of the toothless ones kept living. Some scientists think <a href="http://dx.doi.org/10.1016/j.cub.2016.03.039">not having teeth is what allowed these birds to survive</a>. </p>
<p>Fossils of early toothless birds show <a href="https://doi.org/10.1073/pnas.1011924108">they were able to eat more plant-based food</a> – specifically nuts, fruits and seeds. This meant they relied less on eating other animals than birds with teeth did. Some scientists think this difference in diet became a big advantage after the asteroid impact.</p>
<p>When the asteroid struck Earth, it immediately <a href="https://theconversation.com/curious-kids-what-effect-did-the-asteroid-that-wiped-out-the-dinosaurs-have-on-plants-and-trees-132386">caused massive tsunamis and earthquakes</a>. A giant pulse of heat from the impact caused enormous wildfires near where the asteroid hit. In the months that followed, huge amounts of dust filled the layer of air that surrounds Earth. It blocked the sun, making <a href="https://teachingkidsnews.com/2014/09/21/4-scientists-explain-asteroid-impact-led-dinosaur-extinction/">less light available for plants to grow</a>. </p>
<p>For animals that ate plants, there was much less food. Many went extinct, which spelled trouble for the animals that ate them. </p>
<p>Since so many animal species died – and plants were struggling to get enough sunlight – food would have been hard to find if you were a bird. But if you could peck the ground and find buried seeds or nuts to eat, that might have made all the difference in your <a href="https://doi.org/10.1073/pnas.1011924108">ability to survive as a species</a>.</p>
<h2>How science works</h2>
<p>Of course, it’s possible other factors caused toothless birds to survive while their toothy cousins perished – including luck. </p>
<p>For now, it’s a mystery with no definite answer. This is how science works. Scientists formulate ideas or hypotheses using existing knowledge and information. Then they test their ideas – either by conducting experiments or by gathering more evidence. This information either supports or disproves their ideas.</p>
<p>So the scientists who study bird evolution are ready to revise the story of how birds made it and dinosaurs didn’t as they collect more information from rocks, fossils and <a href="https://theconversation.com/is-it-possible-to-recreate-dinosaurs-from-their-dna-164060">ancient DNA</a>.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p><img src="https://counter.theconversation.com/content/197185/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Lituma does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Birds and dinosaurs lived together for millions of years, but only toothless birds survived the asteroid impact that upended life on Earth.Chris Lituma, Assistant Professor of Wildlife and Fisheries Resources, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1967982022-12-20T19:09:41Z2022-12-20T19:09:41ZNew fossil foot analysis reveals the surprising and varied lifestyles of dinosaur bird ancestors<figure><img src="https://images.theconversation.com/files/502030/original/file-20221220-18-2cacbf.jpg?ixlib=rb-1.1.0&rect=50%2C8%2C5607%2C3718&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Feet of an Andean condor.</span> <span class="attribution"><span class="source">Vladimir Wrangel/Shutterstock</span></span></figcaption></figure><p>Have you ever eaten chicken feet? If you haven’t, you might be surprised to learn there’s actually quite a bit of flesh down there. And scales too! They’re wonderful – and informative – pieces of engineering.</p>
<p>As someone whose speciality is working on fossilised dinosaur skin, I have more than a passing interest in bird feet and the scales of other reptiles (yes, <a href="https://askabiologist.asu.edu/questions/birds-dinosaurs-reptiles">birds are reptiles too</a>).</p>
<p>In a paper <a href="https://www.nature.com/articles/s41467-022-35039-1">published today in Nature Communications</a>, we describe how we used some extraordinary fossils to reveal the varied lifestyles in the transition from ground-dwelling dinosaur to flying bird.</p>
<p>Because the carnivorous <a href="https://ucmp.berkeley.edu/diapsids/saurischia/theropoda.html">theropod dinosaurs</a> – a group of bipedal dinosaurs characterised by hollow bones and three-toed feet – eventually evolved into birds, the two groups share a lot of similarities.</p>
<p>So, we can use birds as a model for reconstructing the behaviour and lifestyles of extinct dinosaurs.</p>
<h2>Multitasking feet</h2>
<p>Birds lack “proper” hands, so their feet have to do twice the work – perching, walking, grasping, manipulating food. They’re naturally well adapted to do those jobs. But all bird feet are not created equal, as the jobs differ between species.</p>
<p>Raptorial birds – think the likes of hawks and falcons – often have <a href="https://doi.org/10.1002/jmor.21057">large, protruding toe pads</a> that act like little fingers to help them grip their prey. Raptorial birds that specialise in catching fish also have spiky scales <a href="https://doi.org/10.1002/jmor.21284">on the underside of the foot</a> to assist in restraining their slippery catch.</p>
<p>Meanwhile, birds that spend more time on the ground (such as emus and kiwis) or perching (crows, sparrows, and so on) have entirely different feet altogether, adapted to the task at hand – or foot. </p>
<p>It had long struck me that if we had the right fossils – if we could only look at their feet – we might find out more about how certain dinosaurs and the first birds behaved, or even hunted.</p>
<h2>Illuminating scales and feathers</h2>
<p>For more than 25 years, <a href="https://doi.org/10.1146/annurev.earth.33.092203.122511">extraordinary fossils of feathered dinosaurs</a> have been emerging at a tremendous rate from Early Cretaceous (roughly 145 million to 100 million years ago) rocks in China.</p>
<p>Fossilised feathers on a slew of species show precisely how feathers changed over time. They transitioned from simple hair-like filaments in ground-dwelling theropods to branching and increasingly more complex modern-style feathers in pennaraptorans (the group most closely related to and including birds), and finally birds themselves.</p>
<p>But feathers are only half the story.</p>
<p>Back in 2015, my colleagues Michael Pittman at the Chinese University of Hong Kong and Tom Kaye at the Foundation for Scientific Advancement pioneered an almost miraculous form of photography called laser stimulated fluorescence (LSF).</p>
<p>This method quite literally illuminates details in fossils that can’t be seen (or are indistinct) with the naked eye. Using LSF, they pored over more than 1,000 fossils of early birds and their dinosaurian relatives.</p>
<p>They identified about a dozen fossils that preserved not only feathers, but, more importantly, the skin and scales surrounding the feet.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An array of seemingly abstract turquoise and golden shapes on a darker background" src="https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=394&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=394&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502032/original/file-20221220-14-87nitv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=394&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A laser-stimulated fluorescence image of a fossil, with inset close-up (c) of scales on one of the digits; the arrows indicate exemplary spiculate reticulate scales.</span>
<span class="attribution"><span class="source">Michael Pittman et al., Nature Communications</span></span>
</figcaption>
</figure>
<p>These fossils ranged from dromaeosaurs (the group of predatory dinosaurs that includes <em>Velociraptor</em>), such as <em>Microraptor</em> and <em>Anchiornis</em>, to more conventional-looking primitive birds, such as <em>Sapeornis</em> and <em>Confuciusornis</em>. </p>
<p>Working with my PhD student, Nathan Enriquez, and another expert on bird feet, Leah Tsang from the Australian Museum, we compared what we saw in the feet of the fossils to the feet of modern birds.</p>
<p>At the same time, Pittman worked with his PhD student, Case Miller, examining the sizes and shapes of the claws for further clues on how they were used.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A flattened representation of a bird-like animal encased in grey stone" src="https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=330&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=330&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=330&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502043/original/file-20221220-15-nvokjs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A well-preserved fossil of <em>Confuciusornis sanctus</em>.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Confuciusornis_male.jpg">Tommy from Arad/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Serious surprises</h2>
<p>At one end of the spectrum, we might expect something like <em>Anchiornis</em> – which has feathers but still had the long tail and features of a ground-based dinosaur – to have few or no indications of the aerial lifestyle of a more bird-like species, such as <em>Confuciusornis</em>.</p>
<p>But this turned out to be only partly true, and there were serious surprises along the way.</p>
<p>Most intriguing was <em>Microraptor</em>, the so-called “four-winged theropod” because it had long flight feathers on its legs and arms; a kind of dinosaurian biplane.</p>
<p>Its feet were almost indistinguishable from modern hawks, suggesting that <em>Microraptor</em> too was a skilled aerial predator capable of taking prey “on the wing”. This was not some clumsy dinosaur “learning” to fly.</p>
<p>In fact, a range of fish, lizards and mammals have all been found preserved in the gut of various <em>Microraptor</em> fossils, which supports the notion of a skilled aerial hunter.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A blue-coloured bird shaped creature with a long tail and sharp claws" src="https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502038/original/file-20221220-14-x7dzft.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An artistic restoration of a <em>Microraptor</em>.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Microraptor_Restoration.png">Fred Wierum/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><em>Anchiornis</em>, while similar in many respects to <em>Microraptor</em> (including a less developed “biplane” design), also had hawk-like feet. However, with limited flight capability, it would have had a more ground-based hunting approach.</p>
<p>The much more bird-like <em>Confuciusornis</em> and <em>Sapeornis</em> had feet well adapted for perching, but other lines of evidence tell us that <em>Confuciusornis</em> was a generalist, more like a magpie or a chicken. </p>
<p><em>Sapeornis</em>, on the other hand, was a thermal soarer that might have supplemented its primarily herbivorous diet with meat, similar to some “herbivorous” vultures. </p>
<p>It’s easy to think of evolution as “linear” or with an end goal: walking dinosaur evolves into feathered dinosaur, feathered dinosaur evolves into flying bird. But that’s a blatantly untrue oversimplification.</p>
<p>It’s equally wrong to think the earliest birds were somehow under-equipped compared to their modern relatives. Our findings help show that, just as birds today occupy a myriad of ecological roles, so too did the dinosaurs.</p>
<p>And they were superbly adapted, regardless of how good they were at flying.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-did-the-velociraptors-have-feathers-119535">Curious Kids: did the velociraptors have feathers?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196798/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phil Bell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The feet of a bird tell us a lot about its life. Newly described, the fossil feet of the ancestors of modern birds reveal how superbly adapted they were to their world.Phil Bell, Palaeontologist, Earth Science Faculty, University of New EnglandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1951802022-11-30T13:37:38Z2022-11-30T13:37:38ZBeware of ‘Shark Week’: Scientists watched 202 episodes and found them filled with junk science, misinformation and white male ‘experts’ named Mike<figure><img src="https://images.theconversation.com/files/497069/original/file-20221123-20-w4v0g6.jpg?ixlib=rb-1.1.0&rect=9%2C3%2C2035%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hammerhead sharks schooling near Costa Rica's Cocos Island.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/GqmhHb">John Voo/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>The Discovery Channel’s annual <a href="https://www.discovery.com/shark-week">Shark Week</a> is the <a href="https://www.washingtonpost.com/news/animalia/wp/2018/07/24/shark-scientists-explain-whats-right-and-whats-wrong-with-shark-week/">longest-running cable television series in history</a>, filling screens with sharky content every summer since 1988. It causes one of the largest temporary increases in U.S. viewers’ attention to any <a href="https://doi.org/10.1371/journal.pbio.3000146">science or conservation topic</a>. </p>
<p>It’s also the largest stage in marine biology, giving scientists who appear on it access to an audience of millions. Being featured by high-profile media outlets can help researchers attract attention and funding that can help super-charge their careers. </p>
<p>Unfortunately, Shark Week is also a missed opportunity. As scientists and conservationists <a href="https://www.outsideonline.com/culture/books-media/what-shark-experts-really-think-about-shark-week/">have long argued</a>, it is a major source of <a href="https://www.npr.org/2015/07/06/420326546/after-sketchy-science-shark-week-promises-to-turn-over-a-new-fin">misinformation</a> and <a href="https://www.bostonmagazine.com/news/2013/08/05/shark-week-megalodon-fake-discovery-channel/">nonsense</a> about sharks, the scientists who study them, and how people can help protect endangered species from extinction.</p>
<p>I am a <a href="https://scholar.google.com/citations?user=xb7noGAAAAAJ&hl=en">marine biologist</a> who worked with five colleagues in 2022 to <a href="https://doi.org/10.1371/journal.pone.0256842">scientifically analyze the content of Shark Week episodes</a>. We tracked down copies of 202 episodes, watched them all and coded their content based on more than 15 variables, including locations, which experts were interviewed, which shark species were mentioned, what scientific research tools were used, whether the episodes mentioned shark conservation and how sharks were portrayed. </p>
<p>Even as longtime Shark Week critics, we were staggered by our findings. The episodes that we reviewed were full of incorrect information and provided a wildly misleading picture of the field of shark research. Some episodes <a href="https://www.earthtouchnews.com/oceans/sharks/experts-shark-weeks-zombie-sharks-harasses-animals/">glorified wildlife harassment</a>, and many missed countless chances to teach a massive audience about shark conservation. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tKXd8Ud1sOo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Sharks are apex predators that are key to maintaining healthy ecosystems, but a 2020 study that surveyed 371 coral reefs found that 20% had no sharks present.</span></figcaption>
</figure>
<h2>Spotlight real solutions</h2>
<p>First, some facts. <a href="https://www.britannica.com/topic/list-of-sharks-skates-and-rays-2075391">Sharks and their relatives</a>, such as rays and skates, are among the most threatened vertebrate animals on Earth. About one-third of all known species are at risk of extinction, thanks mainly to <a href="https://doi.org/10.1016/j.cub.2021.08.062">overfishing</a>. </p>
<p>Many policy solutions, such as setting fishing quotas, creating protected species lists and delineating no-fishing zones, are enacted <a href="https://doi.org/10.1111/acv.12265">nationally or internationally</a>. But there also are countless situations in which increased public attention can help <a href="https://www.press.jhu.edu/books/title/12267/why-sharks-matter">move the conservation needle</a>. For instance, consumers can avoid buying seafood produced using <a href="https://www.montereybayaquarium.org/act-for-the-ocean/sustainable-seafood">unsustainable fishing methods</a> that may accidentally catch sharks.</p>
<p>Conversely, focusing on the wrong problems <a href="https://doi.org/10.1139/facets-2020-0058">does not lead to useful solutions</a>. As one example, enacting a ban on shark fin sales in the U.S. would have little effect on global shark deaths, since the U.S. is only involved in about 1% of the global fin trade, and could <a href="https://doi.org/10.1016/j.marpol.2017.08.026">undermine sustainable U.S. shark fisheries</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A shark caught in a fishing net dangles over the side of a boat with a crew member reaching out." src="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497065/original/file-20221123-24-qt5nyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A crew member aboard a commercial fishing boat off the coast of Maine tries to cut a shark loose from a gillnet. Sharks often are caught accidentally by fishermen pursuing other species.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/crew-member-aboard-a-commercial-fishing-boat-tries-to-cut-a-news-photo/1243631026">Mailee Osten-Tan/SOPA Images/LightRocket via Getty Images</a></span>
</figcaption>
</figure>
<p>The Discovery Channel claims that by attracting massive audiences, Shark Week <a href="https://www.washingtonpost.com/news/animalia/wp/2018/07/24/shark-scientists-explain-whats-right-and-whats-wrong-with-shark-week/">helps educate the public</a> about shark conservation. But most of the shows we reviewed didn’t mention conservation at all, beyond vague statements that sharks need help, without describing the threats they face or how to address them. </p>
<p>Out of 202 episodes that we examined, just six contained any actionable tips. Half of those simply advised against eating <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/shark-fin-soup">shark fin soup</a>, a traditional Asian delicacy. Demand for shark fin soup can contribute to the gruesome practice of “<a href="https://www.discoverwildlife.com/animal-facts/fish/what-is-shark-finning-and-why-is-it-a-problem/">finning</a>” – cutting fins off live sharks and throwing the mutilated fish overboard to die. But finning is not the biggest threat to sharks, and most U.S.-based Shark Week viewers don’t eat shark fin soup.</p>
<h2>Spotlighting divers, not research</h2>
<p>When we analyzed episodes by the type of scientific research they featured, the most frequent answer was “no scientific research at all,” followed by what we charitably called “other.” This category included nonsense like building a submarine that looks like a shark, or a “<a href="https://www.ffjournal.net/item/12437-wasp-water-armor-shark-protection.html">high tech” custom shark cage</a> to observe some aspect of shark behavior. These episodes focused on alleged risk to the scuba divers shown on camera, especially when the devices inevitably failed, but failed to address any research questions.</p>
<p>Such framing is not representative of <a href="https://doi.org/10.1643/OT-19-179R">actual shark research</a>, which uses methods ranging from tracking tagged sharks via satellite to genetic and paleontological studies conducted entirely in labs. Such work may not be as exciting on camera as divers surrounded by schooling sharks, but it generates much more useful data. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/punSQuf-ZwQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gavin Naylor, director of the Florida Program for Shark Research, describes findings from his lab’s analysis of shark genetics.</span></figcaption>
</figure>
<h2>Who’s on camera</h2>
<p>We also were troubled by the “experts” interviewed on many Shark Week shows. The most-featured source, underwater photographer <a href="https://www.youtube.com/watch?v=B7t7jl8e0Mw">Andy Casagrande</a>, is an award-winning cameraman, and episodes when he stays behind the camera can be great. But given the chance to speak, he regularly claims the mantle of science while making dubious assertions – for example, that <a href="https://twitter.com/ABC4EXPLORE/status/1285972513328070689">shark diving while taking LSD</a> is a great way to learn about these animals – or presents well-known shark behaviors as new discoveries that he made, while <a href="https://www.mensjournal.com/adventure/mega-shark-episode-criticized-as-a-low-point-for-shark-week/">misrepresenting what those behaviors mean</a>.</p>
<p>Nor does Shark Week accurately represent experts in this field. One issue is ethnicity: Three of the five most-featured locations on Shark Week are Mexico, South Africa and the Bahamas, but we could count on one hand the number of non-white scientists who we saw featured in shows about their own countries. It was far more common for Discovery to fly a white male halfway around the world than to feature a local scientist. </p>
<p>Moreover, while <a href="https://doi.org/10.3389/feduc.2022.842618">more than half of U.S. shark scientists are female</a>, you <a href="https://www.scientificamerican.com/article/the-dark-side-of-being-a-female-shark-researcher/">wouldn’t know this from watching Shark Week</a>. Among people who we saw featured in more than one episode, there were more white male non-scientists named Mike than women of any profession or name. </p>
<p>In contrast, the Discovery Channel’s chief competitor, National Geographic, is partnering with the professional organization <a href="https://www.misselasmo.org/">Minorities in Shark Sciences</a> to <a href="https://www.nationalgeographic.com/magazine/article/building-a-community-and-fostering-a-love-for-sharks">feature diverse experts</a> on its shows.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1585646957233512450"}"></div></p>
<h2>More substance and better representation</h2>
<p>How could Shark Week improve? Our paper makes several recommendations, and we also participated in a workshop, highlighting diverse voices in our field from all over the world, that focused on <a href="https://safesharks.org/diversifying-shark-media/">improving representation of scientists in shark-focused media</a> </p>
<p>First, we believe that not every documentary needs to be a dry, boring science lecture, but that the information shared on marine biology’s biggest stage should be factually correct and useful. Gimmicky concepts like Discovery’s “<a href="https://www.discovery.com/shows/naked-and-afraid/episodes/naked-and-afraid-of-sharks-2">Naked and Afraid of Sharks 2</a>” – an endurance contest with entrants wearing masks, fins and snorkels, but no clothes – show that people will watch anything with sharks in it. So why not try to make something good? </p>
<p>We also suggest that more scientists seek out media training so they can take advantage of opportunities like Shark Week without <a href="https://gizmodo.com/shark-week-lied-to-scientists-to-get-them-to-appear-in-1619280737">being taken advantage of</a>. Similarly, it would be great to have a “Yelp”-like service that scientists could use to rate their experiences with media companies. Producers who want to feature appropriately diverse scientists can turn to databases like <a href="https://500womenscientists.org/">500 Women Scientists</a> and <a href="https://diversifyeeb.com/">Diversify EEB</a>. </p>
<p>For a decade, concerned scientists and conservationists have <a href="https://www.npr.org/2015/07/06/420326546/after-sketchy-science-shark-week-promises-to-turn-over-a-new-fin">reached out to the Discovery Channel</a> about our concerns with Shark Week. As our article recounts, Discovery has <a href="https://doi.org/10.1371/journal.pone.0256842">pledged in the past</a> to present programming during Shark Week that puts more emphasis on science and less on entertainment – and some episodes <a href="https://twitter.com/whysharksmatter/status/620417258406318080?lang=en">have shown improvement</a>.</p>
<p>But our findings show that many Shark Week depictions of sharks are still problematic, pseudoscientific, nonsensical or unhelpful. We hope that our analysis will motivate the network to use its massive audience to help sharks and elevate the scientists who study them. </p>
<p><em>Editor’s note: The Conversation US contacted Warner Brothers Discovery by phone and email for comment on the study described in this article. The network did not immediately respond or offer comment.</em></p><img src="https://counter.theconversation.com/content/195180/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Shiffman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A study offers evidence that marine biology’s biggest stage is broken, and suggests ways to fix it.David Shiffman, Faculty Research Associate in Marine Biology, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1933872022-11-03T23:59:29Z2022-11-03T23:59:29ZBones of contention: the West Coast whale fossil and the ethics of private collecting<figure><img src="https://images.theconversation.com/files/493377/original/file-20221103-17-lf7e4r.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C2787%2C1825&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>The past can inform the present in more ways than one.</p>
<p>Take the case of the <a href="https://www.stuff.co.nz/national/130294057/police-investigating-removal-of-23millionyearold-fossilised-whale-bones-from-west-coast-rock">23-million-year-old whale fossil</a> recently excavated by a private collector on the West Coast of the South Island. It has angered Karamea locals and Ngāti Waewae, who viewed the fossil as a treasured local attraction, and has led to a <a href="https://www.rnz.co.nz/news/ldr/477419/theft-of-23-million-year-old-fossil-under-investigation">police investigation</a>. </p>
<p>Despite the upset it caused, the actual <a href="https://www.stuff.co.nz/national/130286287/the-legal-quirks-behind-the-theft-of-a-23millionyearold-whale-fossil-cut-from-west-coast-rock">legal situation</a> remains unclear. But the incident has generated significant <a href="https://www.newsroom.co.nz/maori-say-fossil-takers-acted-without-permission">local</a> and <a href="https://www.newsweek.com/wahle-bone-fossils-removed-beach-angered-locals-1754812">international</a> media attention, and raised questions about the role and ethics of private fossil collecting and trading.</p>
<p>In the process, it has reminded us of the way palaeontology provides a unique window into the history of life on Earth, revealing how plants and animals have adapted to our dynamic geological, climatic and human history.</p>
<p>Nearly all species that ever existed are now extinct. Yet their remains are sparse and often destroyed by natural processes or human activity before they can be appreciated or studied. The world is simply too vast, and palaeontologists too few in number, to keep track.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1585239855356940288"}"></div></p>
<h2>The importance of private collectors</h2>
<p>This is where private collectors come in. Driven by a passion for fossils and a desire to protect these fragile echoes of our past, they search land <a href="https://palaeo-electronica.org/content/pdfs/1199.pdf">at a scale</a> no professional institution ever could. Their discoveries have enriched both scientific knowledge and public collections across the world. </p>
<p>Local communities benefit from their findings through sharing knowledge, mounting and contributing to exhibitions, or simply from the awe in which fossils are often held. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/despite-the-myth-deer-are-not-an-ecological-substitute-for-moa-and-should-be-part-of-nzs-predator-free-plan-187840">Despite the myth, deer are not an ecological substitute for moa and should be part of NZ’s predator-free plan</a>
</strong>
</em>
</p>
<hr>
<p>In Aotearoa New Zealand, perhaps the best known example is <a href="https://teara.govt.nz/en/biographies/6w4/wiffen-joan">Joan Wiffen</a>, who discovered our first dinosaurs and became internationally recognised for her achievements. </p>
<p>There are many other success stories of <a href="https://www.nzgeo.com/stories/loves-labours/">fruitful collaborations</a> between <a href="https://palaeo-electronica.org/content/pdfs/1199.pdf">scientists and private collectors</a>. Some have even become so knowledgeable they can describe <a href="https://www.tandfonline.com/doi/pdf/10.1080/00288306.1980.10424122?needAccess=true">new species by themselves</a>.</p>
<p>But sometimes things go wrong, and privately collected fossils become bones of contention.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/493207/original/file-20221103-26-wczedt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">New Zealand’s ‘dinosaur woman’, Joan Wiffen, whose fossil discoveries shed light on a prehistoric world.</span>
<span class="attribution"><span class="source">Wendy St George/GNS Science</span></span>
</figcaption>
</figure>
<h2>The legality and ethics of fossil collecting</h2>
<p>The excavation of archaeological sites (those associated with human activity) requires an <a href="https://www.heritage.org.nz/protecting-heritage/archaeology/standard-archaeological-authority-process">appropriate authority</a> and must involve trained archaeologists. Fossils, however, cannot be managed this way because they occur almost anywhere and in a bewildering variety of forms.</p>
<p>At present, <a href="https://www.stuff.co.nz/national/130286287/the-legal-quirks-behind-the-theft-of-a-23millionyearold-whale-fossil-cut-from-west-coast-rock">rules guiding fossil collecting</a> are mostly tied to the legal status of the land. Excavations on private property require landowner permission, whereas collecting on conservation land generally needs a permit. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-fertiliser-to-phantom-dna-cracks-a-century-old-mystery-about-new-zealands-only-extinct-freshwater-fish-187928">From fertiliser to phantom: DNA cracks a century-old mystery about New Zealand's only extinct freshwater fish</a>
</strong>
</em>
</p>
<hr>
<p>In non-protected public areas, including much of the coast, fossils can usually be collected at will if they are easy to remove. In some cases, this means they must already be lying loose on the ground. In others, limited digging with hand tools may also be allowed. </p>
<p>Larger or mechanical excavations often require resource consent. The exact rules depend on the local council, which means collecting should be planned on a case-by-case basis. </p>
<p>Irrespective of the legal status, any major collecting should be done in consultation with <a href="https://maoridictionary.co.nz/search?keywords=iwi">iwi</a> and (where appropriate) local communities as <a href="https://maoridictionary.co.nz/search?idiom=&phrase=&proverb=&loan=&histLoanWords=&keywords=kaitiaki">kaitiaki</a> (guardians) of the land. As the Karamea whale suggests, some fossils are more powerful in their original setting than in any museum.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492698/original/file-20221101-19-l94d66.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ethical fossil collecting: volunteers at the 16-19 million-year-old St Bathans deposits in Central Otago.</span>
<span class="attribution"><span class="source">Nic Rawlence/University of Otago</span></span>
</figcaption>
</figure>
<h2>Trading in fossils</h2>
<p>While <a href="https://theconversation.com/dinosaur-embryo-returned-to-china-but-many-fossils-fall-victim-to-illegal-trade-and-poor-protection-77349">fossil trading can be a murky world</a>, it often helps bring scientifically important discoveries to light. Paying for fossils may seem odd, but has a long precedent. Take <em><a href="https://www.livescience.com/24745-archaeopteryx.html">Archaeopteryx</a></em>, the “missing link” between dinosaurs and birds: many of the famous specimens now in museums were bought from private owners. </p>
<p>Putting a price on fossils often reflects the time, effort and experience required to collect them. It can also reflect their rarity, scientific interest, exhibition value and quality of preservation. In many ways, it is comparable to acquiring other cultural, historical and natural treasures. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-did-ancient-moa-survive-the-ice-age-and-what-can-they-teach-us-about-modern-climate-change-183350">How did ancient moa survive the ice age – and what can they teach us about modern climate change?</a>
</strong>
</em>
</p>
<hr>
<p>Acquiring fossils for museums is condoned by professional associations like the <a href="https://vertpaleo.org/">Society of Vertebrate Paleontology</a>. But trading is problematic when it <a href="https://www.wired.co.uk/article/dinosaur-t-rex-auction-sale-private-fossil-trade">relegates important specimens to private ownership</a> and therefore inaccessible to scientists, locals and the general public. </p>
<p>It’s legal to collect, own and trade fossils without a permit in New Zealand, so long as they stay in the country. Fossil exports are regulated by the <a href="https://www.legislation.govt.nz/act/public/1975/0041/latest/DLM432116.html">Protected Objects Act</a>, which prevents scientifically important specimens from being sent abroad permanently. </p>
<p>As a result, the market for New Zealand fossils is relatively small and largely comprised of local collectors and museums. Eventually, many of these specimens do make their way into public ownership.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/493176/original/file-20221103-15-vdyjys.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Several <em>Archaeopteryx</em> specimens, which helped scientists show dinosaurs evolved into birds, were sold to museums by private collectors.</span>
<span class="attribution"><span class="source">Getty Images</span></span>
</figcaption>
</figure>
<h2>The future of the past</h2>
<p>Incidents like the one near Karamea raise the question of whether New Zealand is doing enough to protect its fossil heritage. Similar concerns are currently driving a public campaign to save <a href="https://www.rnz.co.nz/national/programmes/ninetonoon/audio/2018858541/the-fossil-treasures-of-foulden-maar">Foulden Maar</a>, a nationally significant fossil site in Central Otago. </p>
<p>Protections can apply to <a href="https://www.oparara.co.nz/history-of-the-oparara">particular places</a> or to particular kinds of fossils. Both have some drawbacks, however. Red tape can severely hinder research within protected sites. And sweeping protections applied to whole classes of objects can be difficult to enforce and might drive fossil traders underground.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=488&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=488&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=488&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=613&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=613&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492700/original/file-20221101-20-1bkjoz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=613&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A partnership between archaeologist Matt Schmidt, palaeontologists and local iwi was critical for the excavation of a moa fossil on Rakiura Stewart Island.</span>
<span class="attribution"><span class="source">Alex Verry/University of Otago</span></span>
</figcaption>
</figure>
<p>Applied correctly, however, the current legal and ethical guidelines work well, despite recent exceptions. Given their colonial origins and public facing role, museums should also be <a href="https://theconversation.com/how-to-hunt-fossils-responsibly-5-tips-from-a-professional-palaeontologist-156861">raising awareness</a> about ethical fossil collecting. Knowledgeable private collectors have, and always will, play an important role in New Zealand palaeontology.</p>
<p>Rather than pursuing law changes that create extra bureaucracy, we encourage stakeholders to join forces in protecting the interests of iwi and communities, save important fossils from being lost, and keep telling the story of ancient Aotearoa.</p><img src="https://counter.theconversation.com/content/193387/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society Te Apārangi Marsden Fund. </span></em></p>Despite causing hurt and offence, the legality of removing a whale fossil from the West Coast remains unclear. So what rules and laws govern amateur fossil hunting, and should they be strengthened?Nic Rawlence, Senior Lecturer in Ancient DNA, University of OtagoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1898552022-09-30T12:28:10Z2022-09-30T12:28:10ZDo multimillion-dollar dinosaur auctions erode trust in science?<figure><img src="https://images.theconversation.com/files/485915/original/file-20220921-8022-4e742t.jpg?ixlib=rb-1.1.0&rect=74%2C0%2C7011%2C4716&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sotheby's sold a 77 million-year-old Gorgosaurus skeleton for over $6 million in July 2022.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.co.uk/detail/news-photo/gorgosaurus-skeleton-is-on-display-during-a-press-preview-news-photo/1406957644?adppopup=true">Alexi Rosenfeld/Getty Images</a></span></figcaption></figure><p>Dinosaurs are in the news these days, but it’s not just for groundbreaking discoveries.</p>
<p>More and more paleontologists are ringing alarm bells about high-profile auctions in which dinosaur fossils sell for outrageous sums. The most recent example involves <a href="https://news.artnet.com/market/sothebys-gorgosaurus-skeleton-8-million-2142470">a 77 million-year-old <em>Gorgosaurus</em> skeleton</a> that Sotheby’s sold for over US$6 million in August 2022.</p>
<p>But that’s not even close to the most anyone ever paid for a dinosaur. In May 2022, Christie’s sold a <em>Deinonychus</em> skeleton for <a href="https://news.artnet.com/art-world/dinosaur-skeleton-christies-2114482">$12.4 million</a>. And a couple of months before that, Abu Dhabi’s Department of Culture and Tourism paid an <a href="https://www.nationalgeographic.com/science/article/stan-the-t-rex-found-worlds-most-expensive-fossil-finds-home-in-a-new-museum">eye-popping $31.8 million for Stan</a>, a remarkably complete <em>T. rex</em> from South Dakota’s Hell Creek Formation that’s going to be the centerpiece of the Persian Gulf city’s new natural history museum.</p>
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<p>Some scientists are so dismayed they are speaking out. University of Edinburgh paleontologist Steve Brusatte <a href="https://www.dailymail.co.uk/sciencetech/article-11117517/Furious-paleontologists-blast-auction-houses-letting-super-rich-buy-dinosaur-specimens.html">told the Daily Mail</a> that auction houses turn valuable specimens into “little more than toys for the rich.” Thomas Carr from Carthage College in Wisconsin was <a href="https://www.dailymail.co.uk/sciencetech/article-11117517/Furious-paleontologists-blast-auction-houses-letting-super-rich-buy-dinosaur-specimens.html">even more forthright</a>, saying, “Greed for money is what drives these auctions.” He also complained that wealthy elites – <a href="https://www.vanityfair.com/hollywood/2013/10/nicolas-cage-leonardo-dicaprio-dinosaur-skull">including actors Nicholas Cage and Leonardo DiCaprio</a> – are competing to acquire the best specimens in a game of juvenile one-upmanship, describing them as “thieves of time.”</p>
<p>Most commenters trace the booming market for dinosaurs <a href="https://www.fieldmuseum.org/blog/sue-t-rex">back to Sue, the largest and most complete <em>T. rex</em> ever found</a>. After the FBI confiscated it from <a href="https://www.bhigr.com/">the same group of fossil hunters</a> who found Stan, the Field Museum of Natural History in Chicago acquired it – with financial backing from Disney and McDonald’s – for over $8 million in 1997. </p>
<p>But as I document in my recent book, “<a href="https://www.amazon.com/Assembling-Dinosaur-Hunters-Tycoons-Spectacle/dp/067473758X/ref=sr_1_1?keywords=rieppel+assembling+the+dinosaur&qid=1662586515&sprefix=rieppel+ass%2Caps%2C61&sr=8-1">Assembling the Dinosaur</a>,” the commercial specimen trade is as old as the science of paleontology itself. And its history shows the debate over whether dinosaurs ought to be bought and sold involves much deeper questions about the long-standing but hotly contested relationship between science and capitalism.</p>
<h2>Two sides of the debate</h2>
<p>Paleontologists have good reason to oppose the commercial sale of valuable fossils. Science is fundamentally a community enterprise, and if specimens aren’t available for public examination, paleontologists have no way to assess whether new findings are true. What if a particularly outlandish theory is based on a fraudulent specimen?</p>
<p>This happens more often than you’d think. <a href="https://www.nature.com/articles/35001723">In the late 1990s</a> a private collector purchased what appeared to be a feathered dinosaur at the Tucson Gem and Mineral Show. National Geographic subsequently reported on it to great fanfare, claiming it was a “missing link” between dinosaurs and modern birds. When scientists grew suspicious, <a href="https://www.nature.com/articles/420285a">they found</a> that the so-called “<em>Archaeoraptor</em>” fossil combined pieces of several distinct specimens to make a chimerical creature that never existed.</p>
<p>But <a href="https://books.google.com/books/about/Rex_Appeal.html?id=o5TuAAAAMAAJ">commercial fossil hunters</a> make a compelling point, too. Most fossils first come to light through the natural process of erosion. Eventually, however, erosion also destroys the specimen itself – and there simply aren’t enough scientists to find every fossil before it is lost. Hence, the argument goes, commercial collectors should be celebrated for saving specimens by digging them up.</p>
<h2>Wealthy philanthropists distance themselves</h2>
<p>Both sides of the argument make a compelling point. But as the fiasco around “<em>Archaeoraptor</em>” reveals, it’s worth asking whether financial incentives erode trust.</p>
<p>Dinosaurs first came to the attention of geologists during the 19th century. In fact, these gigantic lizards did not acquire their name until the comparative anatomist Richard Owen invented <a href="https://books.google.com/books?id=mSTs2oyhdS0C&vq=dinosauria&pg=PA190#v=onepage&q&f=false">the biological category “Dinosauria”</a> in 1842. </p>
<figure class="align-right ">
<img alt="Portrait of man with white beard wearing a suit seated in a chair." src="https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=797&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=797&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=797&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1001&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1001&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486846/original/file-20220927-14-pwsm69.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1001&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Industrialist and philanthropist Andrew Carnegie had a dinosaur species, <em>Diplodocus carnegii</em>, named after him.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Andrew_Carnegie#/media/File:Andrew_Carnegie,_by_Theodore_Marceau.jpg">Library of Congress</a></span>
</figcaption>
</figure>
<p>At that time, scientists <a href="https://doi.org/10.1177/0306312715570650">did not treat dinosaurs any differently</a> from other valuables that could be dug out of the ground, such as gold, silver and coal. Museums purchased most of their fossils from commercial collectors, often using funds donated by wealthy industrialists like Andrew Carnegie, who even had a dinosaur named after him: <em><a href="https://upittpress.org/books/9780822966524/">Diplodocus carnegii</a></em>.</p>
<p>That started to change at the very end of the 19th century, when there was a concerted effort to decommodify dinosaur bones, and museums began to distance themselves from the commercial specimen trade. </p>
<p>One impetus came from museums’ wealthy benefactors, <a href="https://link.springer.com/book/10.1057/9780230115569">who sought to demarcate</a> their charitable activities from the unsavory world of commerce. Philanthropists like Carnegie and J.P. Morgan gave money to cultural institutions because they wanted to signal their refined taste, their appreciation for learning and their republican virtues – not to enter into a business transaction.</p>
<p>Moreover, <a href="https://www.hup.harvard.edu/catalog.php?isbn=9780674979857">the first Gilded Age resembled the present</a> in that it, too, saw a sharp increase in economic inequality. This led to widespread class conflict, which could be <a href="https://www.haymarketbooks.org/books/1339-when-workers-shot-back">remarkably violent and bloody</a>. Afraid that incendiary labor leaders would bring the industrial economy to its knees, wealthy elites began <a href="https://www.google.com/books/edition/The_Gospel_of_Wealth_and_Other_Timely_Es/q5ALvRp61wgC?hl=en&gbpv=1&pg=PR3&printsec=frontcover">using public displays of conspicuous generosity</a> to demonstrate that American capitalism could yield public goods in addition to profits. </p>
<p>For all these reasons, it was essential for their philanthropic activities to be seen as selfless acts of genuine altruism, utterly divorced from the cutthroat competition of the marketplace.</p>
<h2>Scientists take control</h2>
<p>At the same time, paleontologists <a href="https://www.press.jhu.edu/books/title/3181/scientists-and-swindlers">embraced the language of “pure science”</a> to claim they produced knowledge for its own sake – not financial gain.</p>
<p>By arguing that their work was free from the corrupting influence of money, scientists made themselves <a href="https://press.uchicago.edu/ucp/books/book/chicago/S/bo3626633.html">more trustworthy</a>.</p>
<p>Ironically, scientists found they could attract more funds by claiming to be completely uninterested in money, fashioning themselves into ideal recipients for the philanthropic largesse of wealthy elites. But that further necessitated a clear demarcation between the the culture of capitalism and the practice of science, which entailed a reluctance to acquire specimens via purchase.</p>
<figure class="align-center ">
<img alt="Old photograph of three men working on an excavation site." src="https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=518&fit=crop&dpr=1 754w, https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=518&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/486848/original/file-20220927-14-5t5l3y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=518&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">At the turn of the 20th century, museums started funding excavations to unearth dinosaur bones.</span>
<span class="attribution"><a class="source" href="https://museum.wales/media/48597/thumb_1024/bone-cabin-quarry-1898-PublicDomain.jpg">Museum Wales</a></span>
</figcaption>
</figure>
<p>As scientists began shunning the commercial specimen trade, museums set about using the generous donations of wealthy philanthropists to mount increasingly ambitious expeditions that allowed scientists to collect fossils themselves.</p>
<h2>Dinosaurs in the New Gilded Age</h2>
<p>But their ability to control the private market for dinosaur bones did not last forever. With the United States in the middle of what some call a <a href="https://www.vox.com/first-person/2019/4/1/18286084/gilded-age-income-inequality-robber-baron">New Gilded Age</a>, it has come roaring back. </p>
<p>Today, the most spectacular dinosaur fossils often hail from the Jehol formation of <a href="https://www.nature.com/articles/nature01420">northeastern China</a>. And more often than not, they are purchased from local farmers who supplement their incomes by hunting for fossils on the side. </p>
<p>As a result, the question of whether commercial incentives erode trust is back with a vengeance. Li Chun, a professor at Beijing’s prestigious Institute for Vertebrate Paleontology and Paleoanthropology, <a href="http://doi.org/10.1126/science.330.6012.1740">estimates that</a> more than 80% of all marine reptiles on display in Chinese museums have been deceptively altered to some degree, often to increase their value.</p>
<p>The age-old worry about whether the profit motive threatens to undermine the values of science is real. But it is hardly unique to paleontology. </p>
<p>The spectacular <a href="https://www.penguinrandomhouse.com/books/549478/bad-blood-by-john-carreyrou/">implosion of Theranos</a>, a tech startup that secured more than $700 million in venture capital based on false promises of having developed a better way to conduct blood tests, is just just a particularly high-profile example of commercial deceit paired with scientific misconduct. So much scientific research is now being paid for by people who have a commercial stake in the knowledge produced – and you can see the ramifications in everything from <a href="https://www.scientificamerican.com/article/exxon-knew-about-climate-change-almost-40-years-ago/">Exxon’s decision to hide its early research on climate change</a> to Moderna’s recent move to <a href="https://www.nytimes.com/2022/08/26/business/moderna-covid-vaccine-lawsuit.html">begin enforcing its patent</a> on the mRNA technology behind the most effective COVID-19 vaccines. </p>
<p>Is it any wonder that <a href="https://www.pewresearch.org/science/2022/02/15/americans-trust-in-scientists-other-groups-declines/">so many people have lost trust in science</a>?</p><img src="https://counter.theconversation.com/content/189855/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lukas Rieppel has received funding from the National Science Foundation and the Mellon Foundation, among others.</span></em></p>Derided as ‘toys for the rich,’ the specimens being bought and sold raise broader questions about the relationship between science and capitalism.Lukas Rieppel, Associate Professor of History, Brown UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1892562022-08-24T15:30:47Z2022-08-24T15:30:47ZBreakthrough shows humans were already standing on their own two feet 7 million years ago<figure><img src="https://images.theconversation.com/files/480806/original/file-20220824-12-6oj7od.jpeg?ixlib=rb-1.1.0&rect=15%2C10%2C3521%2C2461&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artwork in the Djourab desert, Chad, gives a taste of how our oldest ancestors got around.</span> <span class="attribution"><span class="source">Sabine Riffaut, Guillaume Daver, Franck Guy / Palevoprim / CNRS – Université de Poitiers / MPFT</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>The study of present-day species has delivered a clear verdict on humanity’s place in the living world: right alongside chimpanzees and bonobos. However, this does not tell us much about <a href="https://theconversation.com/when-humans-split-from-the-apes-55104">our earliest human representatives</a>, their biology or geographical distribution – in short, how we became human. For this, we mainly have to rely on the morphology of frustratingly rare fossils, given <a href="https://serious-science.org/paleogenetics-1936">paleogenetic</a> information is only preserved for recent periods – and even then, in rather cool climates.</p>
<p>Since the 1960s and the identification of the very early age of <em>Australopithecus</em> – including the famous <a href="https://www.nature.com/scitable/knowledge/library/lucy-a-marvelous-specimen-135716086/">Lucy</a> aged 3.18 Ma (million years ago), discovered in 1974 in Ethiopia – <a href="https://www.hominides.com/html/dossiers/bipedalism.php">the acquisition of bipedalism</a> has been regarded as a decisive step in human evolution. Indeed, it is an essential feature that marks the transition from non-human to human long before the significant increase in the size of our brain.</p>
<p>There has been much anticipation of <a href="https://www.nature.com/articles/s41586-022-04901-z">our study</a>, published on 24 August in <em>Nature</em>, on the skeleton of <a href="https://www.medecinesciences.org/fr/articles/medsci/full_html/2006/04/medsci2006223p250/medsci2006223p250.html"><em>Sahelanthropus tchadensis</em></a>, who is a candidate for the oldest-known representative of humanity. </p>
<p>So, was our distant ancestor a biped or not – i.e., human or not human? In reality, asking the question in these terms borders on circular reasoning. Given we have yet to discover the last common ancestor we share with chimpanzees, we do not know the initial state of human locomotion – bipedal or otherwise.</p>
<h2>Were the first representatives of humanity bipeds?</h2>
<p>Until now, the earliest data available to us were the limb bones of <a href="https://en.wikipedia.org/wiki/Orrorin"><em>Orrorin</em></a> (6 Ma, Kenya) and <a href="https://en.wikipedia.org/wiki/Ardipithecus"><em>Ardipithecus</em></a> (5.8 Ma–4.2 Ma, Ethiopia), which practised a different type of bipedalism from that of more recent species. It turns out bipedalism is not an invariable feature of humanity and has its own history within our history. The right question is therefore: were the first representatives of humanity bipedal, and if so, to what extent and how? This is the question that our <a href="http://palevoprim.labo.univ-poitiers.fr/missing-limbs/">Franco-Chadian team</a> sought to answer by studying the much older remains (about 7 Ma) of <em>Sahelanthropus</em>.</p>
<p>The existence of <em>Sahelanthropus</em> was initially <a href="https://www.nature.com/articles/nature00879">deduced in 2002</a> from a distorted but otherwise well-preserved cranium (nicknamed Toumaï) and a few other cranio-dental specimens discovered by the <a href="http://palevoprim.labo.univ-poitiers.fr/2018/06/19/tchad/">Franco-Chadian palaeoanthropological mission</a> (founded and directed by Michel Brunet) at Toros-Menalla in the Djourab Desert in Chad, representing at least three individuals. The study is primarily based on the morphology of the teeth, face and braincase that this species has been compared with more recent human fossils.</p>
<p>[<em>More than 80,000 readers look to The Conversation France’s newsletter for expert insights into the world’s most pressing issues</em>. <a href="https://theconversation.com/fr/newsletters/la-newsletter-quotidienne-5?utm_source=inline-70ksignup">Sign up now</a>]</p>
<p>The limb bones described in our article include a partial left femur (thigh bone) and two left and right ulnae (together with the radius, the ulna is one of the two bones in the forearm that form our elbow). These bones were found in the same locality and year as the cranium, but <a href="https://www.nature.com/articles/d41586-018-00972-z">were identified later</a> in 2004. They most likely belong to the same species as the cranium, as only one large primate was identified out of nearly 13,800 fossils representing about 100 different vertebrates across 400 localities in Toros-Menalla. However, it is not known whether this femur, ulnae and cranium belong to the same individual, as at least three different individuals were found onsite.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=369&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=369&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=369&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=463&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=463&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480807/original/file-20220824-20-q8sbdu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=463&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">3D digitised models of the three limb bones of TM 266 attributed to <em>Sahelanthropus tchadensis</em> (left, femur in posterior and medial views; right, the two ulnae in anterior and lateral views).</span>
<span class="attribution"><span class="source">Franck Guy/CNRS/Université de Poitiers/MPFT</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>A number of factors slowed down our research, which began in 2004. For example, we were required to prioritise field research of other postcranial remains, while we struggled to analyse fragmentary material. We eventually relaunched the project in 2017 and concluded it five years later.</p>
<h2>Bones studied from every angle</h2>
<p>Given the poor preservation of these long bones (the femur, for example, has lost both ends), <a href="https://www.sciencedirect.com/science/article/abs/pii/S0047248420301597">brief analyses</a> cannot provide reliable interpretations. We therefore studied them from all angles, both in terms of their external morphology and internal structures.</p>
<p>To reduce uncertainty, we employed an extensive set of methods, including direct observations and biometric measurements, 3D image analysis, shape analysis (<a href="https://en.wikipedia.org/wiki/Morphometrics">morphometrics</a>) and biomechanical indicators. We compared the Chadian material with present-day and fossil specimens through the prism of 23 criteria. Taken separately, none can be used to propose a categorical interpretation of the material – indeed, there are no “magic” traits in paleoanthropology, and all will be subject to discussion within the scientific community.</p>
<p>Taken together, however, these traits result in an interpretation of these fossils that is far more parsimonious than any alternative hypothesis. This combination therefore indicates that <em>Sahelanthropus</em> practised habitual bipedalism – i.e., that is as a regular means of locomotion. In this case, bipedalism was probably used for movement on the ground as well as in trees. In the latter case, it was most likely accompanied by a quadrupedal gait accompanied by the grasping of branches, in contrast from the quadrupedal gait practised by gorillas and chimpanzees, known as “knuckle walking”, in which weight is supported by the backs of the phalanges.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480823/original/file-20220824-24-m7s9pf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Relationships between humans, gorillas and chimpanzees. Bipedalism gradually became the means of locomotion within the human branch from a combination of bipedalism and tree climbing, as documented by Sahelanthropus.</span>
<span class="attribution"><span class="source">Franck Guy/CNRS/Université de Poitiers/MPFT</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>The results are consistent with observations made on <em>Orrorin</em> and <em>Ardipithecus</em>, and have several implications. First, they reinforce the concept of a very early form of bipedalism in human history coexisting with other modes of locomotion. Thus there was no “sudden” appearance of a characteristic unique to humanity right from the start, but a long, slow transition spanning millions of years. </p>
<p>This phase of human evolution thus took place in ways that are quite common throughout the history of life and the globe, and it reminds us that our species is but a fragment of biodiversity. This fact alone should lead us to rethink our attitude toward the <a href="https://theconversation.com/rapport-de-lipbes-sur-la-biodiversite-lheure-nest-plus-aux-demi-mesures-116473">living world</a> and the <a href="https://theconversation.com/comprendre-la-notion-de-limites-planetaires-145227">parameters</a> that govern the hospitality of our planet.</p>
<p>Second, the characteristics of <em>Sahelanthropus</em>, <em>Orrorin</em> and <em>Ardipithecus</em> suggest the ancestor we share with chimpanzees was neither chimpanzee-like nor the exclusive biped we have become. Contrary to the hypothesis that chimpanzees and bonobos <a href="https://www.nature.com/articles/d41586-022-02226-5">retained their ancestral morphology</a>, their particular combination of vertical climbing and “knuckle walking” more likely evolved well after our divergence.</p>
<p>Finally, if <em>Sahelanthropus tchadensis</em> is a witness of human diversity among others, it is, to this day, the only known habitual bipedal species of that age. Considering the whole, weakly diversified, hominoid fossil record of Africa and Eurasia at the end of the Miocene (after 10 Ma), the acquisition of bipedalism by the human branch on the African continent remains the only well-documented hypothesis to date. At this stage, the bipedalism appears to be part of an opportunistic locomotor repertoire – flexible, able to take advantage of different environments – that corresponds well to the diversified paleoenvironment of Toros-Menalla as reconstructed by the geologists, paleobotanists and paleontologists of our team.</p>
<p>This work was developed through a strong North-South scientific collaboration in palaeoanthropology, namely between the <a href="http://palevoprim.labo.univ-poitiers.fr/2018/06/19/tchad/">PALEVOPRIM laboratory</a>, the palaeontology department of the <a href="https://www.universite-ndjamena.td/">University of N’Djaména</a> and the <a href="https://www.cnar-cnrd.org/index.php/accueil">Centre National de Recherche pour le Développement</a>. These three bones belong to the Chadian heritage and will soon return to their country. At the same time, our fruitful collaboration will continue through new studies of the material as well as new field research that follows in the footsteps of the much-missed <a href="https://theconversation.com/laustralopitheque-lucy-ne-fut-pas-la-seule-passion-dyves-coppens-185927">Yves Coppens</a>, pioneer of paleontological research in Chad.</p>
<hr>
<p><em>This article was co-authored by Abderamane Moussa (University of N’Djaména, Chad).</em></p><img src="https://counter.theconversation.com/content/189256/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jean-Renaud Boisserie is associated researcher to the French Center for Ethiopian Studies.</span></em></p><p class="fine-print"><em><span>Andossa Likius, Clarisse Nekoulnang Djetounako, Franck Guy, Guillaume Daver, Laurent Pallas, Mackaye Hassane Taisso et Patrick Vignaud ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur poste universitaire.</span></em></p>New research shows our oldest ancestors were able to walk as well as evolve in trees.Jean-Renaud Boisserie, Directeur de recherche au CNRS, paléontologue, Université de PoitiersAndossa Likius, Mission Paléoanthropologique Franco-Tchadienne, Université de N'Djamena (Tchad)Clarisse Nekoulnang Djetounako, Enseignante chercheure en paléontologie, Université de N'Djamena (Tchad)Franck Guy, Paléoanthropologue, Université de PoitiersGuillaume Daver, Maîtres de conférences en paléoanthropologie, Université de PoitiersLaurent Pallas, Paléontologue, Kyoto UniversityMackaye Hassane Taisso, Paléontologue, Université de N'Djamena (Tchad)Patrick Vignaud, Pr. Paléontologie, Université de PoitiersLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1879962022-08-22T20:01:37Z2022-08-22T20:01:37ZRevelations from 17-million-year-old ape teeth could lead to new insights on early human evolution<figure><img src="https://images.theconversation.com/files/476868/original/file-20220801-60917-921i4s.JPG?ixlib=rb-1.1.0&rect=18%2C156%2C4007%2C2861&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fossilised jaws from the 17 million-year-old Kenyan ape _Afropithecus turkanensis_.</span> <span class="attribution"><span class="source">Tanya M. Smith/National Museums of Kenya</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The timing and intensity of the seasons shapes life all around us, including <a href="https://doi.org/10.1046/j.1461-0248.2002.00370.x">tool use</a> by birds, the <a href="https://doi.org/10.1371/journal.pone.0077191">evolutionary diversification</a> of giraffes, and the <a href="https://doi.org/10.1016/j.jhevol.2014.02.009">behaviour</a> of our close primate relatives. </p>
<p>Some scientists suggest early humans and their ancestors also evolved due to <a href="https://humanorigins.si.edu/research/climate-and-human-evolution/climate-effects-human-evolution">rapid changes</a> in their environment, but the physical evidence to test this idea has been elusive – until now.</p>
<p>After more than a decade of work, we’ve developed an approach that leverages tooth chemistry and growth to extract information about seasonal rainfall patterns from the jaws of living and fossil primates. </p>
<p>We share our findings in <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.2123366119">a collaborative study</a> just published in Proceedings of the National Academy of Sciences.</p>
<h2>Teeth are environmental time machines</h2>
<p>During childhood our teeth grow in <a href="https://doi.org/10.1002/evan.20176">microscopic layers</a> similar to the growth rings found in trees. Seasonal changes in the world around us, such as droughts and monsoons, influence our body chemistry. The evidence of such changes is recorded in our teeth. </p>
<p>That’s because the oxygen isotope composition of drinking water <a href="https://www.annualreviews.org/doi/10.1146/annurev.earth.24.1.225">naturally varies</a> with temperature and precipitation cycles. During warm or dry weather, surface waters accumulate more heavy isotopes of oxygen. During cool or wet periods, lighter isotopes become more common. </p>
<p>These temporal and climatic records remain locked inside fossilised tooth enamel, which can maintain <a href="https://www.degruyter.com/document/doi/10.1515/9781501509636-015/html">chemical stability</a> for millions of years. But the growth layers are generally so small that most chemical techniques can’t measure them. </p>
<p>To get around this problem, we teamed up with geochemist Ian Williams at the Australian National University, who runs the world-leading <a href="https://science.anu.edu.au/research/facilities/sensitive-high-resolution-ion-microprobe-shrimp">Sensitive High Resolution Ion Microprobe</a> (SHRIMP) facilities.</p>
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<iframe src="https://player.vimeo.com/video/740972391" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
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<p>In our study, we collected detailed records of tooth formation and enamel chemistry from slices of more than two dozen wild primate teeth from equatorial Africa.</p>
<p>We also analysed two fossil molars from an unusual large-bodied ape called <em>Afropithecus turkanensis</em> that lived in Kenya 17 million years ago. Diverse groups of apes inhabited Africa during this period, roughly 10 million years before the evolution of our early ancestors, the hominins.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=199&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=199&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=199&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=250&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=250&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476866/original/file-20220801-13732-4lab4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=250&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Thin slice of a 17-million-year-old <em>Afropithecus</em> tooth illuminated with polarised light reveals progressive growth (right to left). We microsampled oxygen isotopes weekly for over three years, or 1148 days, in this tooth.</span>
<span class="attribution"><span class="source">Tanya M. Smith</span></span>
</figcaption>
</figure>
<h2>Diving into an ancient African landscape</h2>
<p>Several aspects of our research are helpful for understanding the link between environmental patterns and primate evolution.</p>
<p>First, we observe a direct relationship between historic African rainfall patterns and primate tooth chemistry. This is the first test of a highly influential idea in archaeological and earth sciences applied to wild primates: that teeth can record fine details of seasonal environmental change.</p>
<p>We are able to document annual west African rainy seasons and identify the end of east African droughts. In other words, we can “see” the storms and seasons that occur during an individual’s early life.</p>
<p>And this leads into another important aspect. We provide the largest record of primate oxygen isotope measurements collected so far, from diverse environments in Africa that may have resembled those of ancestral hominins.</p>
<p>Lastly, we’ve been able to reconstruct annual and semi-annual climate cycles, and marked environmental variation, from information held within the teeth of the two fossil apes.</p>
<p>Our observations support the hypothesis that <em>Afropithecus</em> developed certain features to adapt to a seasonal climate and challenging landscape. For example, it had specialised dental traits for hard object feeding, as well as a longer period of molar growth compared with earlier apes and monkeys – consistent with the idea that it consumed more seasonally varied foods. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=245&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=245&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=245&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=308&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=308&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476867/original/file-20220801-44070-w6qtal.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=308&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Oxygen isotopes from the teeth of <em>Afropithecus</em> reveal wet and dry seasons that occurred 17 million years ago in eastern Africa.</span>
<span class="attribution"><span class="source">Daniel R. Green & Tanya M. Smith</span></span>
</figcaption>
</figure>
<p>We conclude our work by comparing data from <em>Afropithecus</em> to earlier studies of fossil hominins and monkeys from the same region in Kenya. Our detailed microsampling shows just how sensitive tooth chemistry is to fine-scale climate variation.</p>
<p>Previous studies of more than 100 fossil teeth have missed the most interesting part of oxygen isotope compositions in teeth: the huge seasonal variation on the landscape. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/what-teeth-can-tell-about-the-lives-and-environments-of-ancient-humans-and-neanderthals-104923">What teeth can tell about the lives and environments of ancient humans and Neanderthals</a>
</strong>
</em>
</p>
<hr>
<h2>Research potential closer to home</h2>
<p>This novel research approach, coupled with our fossil ape findings and modern primate data, will be crucial for future studies of hominin evolution – especially in Kenya’s famous Turkana Basin. </p>
<p>For example, some researchers have suggested that seasonal differences <a href="https://www.science.org/doi/full/10.1126/science.1133827">in foraging</a> and <a href="https://www.science.org/doi/full/10.1126/science.1135741">stone tool use</a> helped hominins evolve and coexist in Africa. This idea has been hard to prove or disprove, in part because seasonal climatic processes have been hard to tease out of the fossil record.</p>
<p>Our approach could also be extended to animal remains from rural Australia to gain further insight into historic climate conditions, as well as the prehistoric environmental changes that shaped Australia’s unique modern landscapes. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/archaeology-can-help-us-prepare-for-climates-ahead-not-just-look-back-101823">Archaeology can help us prepare for climates ahead – not just look back</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/187996/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tanya M. Smith receives funding from the Australian Academy of Science and the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Daniel Green receives funding from Columbia University, the Leakey Foundation, the American National Science Foundation, and the Kenyan Turkana Basin Institute.</span></em></p>Cutting-edge analysis of fossil ape teeth reveals ancient seasonal change in Africa, long before human ancestors appeared. The method will be crucial for the future study of early hominins.Tanya M. Smith, Professor in the Australian Research Centre for Human Evolution & Griffith Centre for Social and Cultural Research, Griffith UniversityDaniel Green, Postdoctoral Research Scientist, Columbia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1861162022-07-20T15:03:08Z2022-07-20T15:03:08ZMeet Qikiqtania, a fossil fish with the good sense to stay in the water while others ventured onto land<figure><img src="https://images.theconversation.com/files/474947/original/file-20220719-12-fg9agl.jpg?ixlib=rb-1.1.0&rect=4%2C350%2C2686%2C1847&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's vision of *Qikiqtania* enjoying its fully aquatic, free-swimming lifestyle.</span> <span class="attribution"><span class="source">Alex Boersma</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Approximately 365 million years ago, one group of fishes left the water to live on land. These animals were early <a href="https://ucmp.berkeley.edu/vertebrates/tetrapods/tetraintro.html">tetrapods</a>, a lineage that would radiate to include many thousands of species including amphibians, birds, lizards and mammals. Human beings are descendants of those early tetrapods, and we share the legacy of their water-to-land transition.</p>
<p>But what if, instead of venturing onto the shores, they had turned back? What if these animals, just at the cusp of leaving the water, had receded to live again in more open waters?</p>
<p><a href="https://www.nature.com/articles/s41586-022-04990-w">A new fossil</a> suggests that one fish, in fact, did just that. In contrast to other closely related animals, which were using their fins to prop their bodies up on the bottom of the water and perhaps occasionally venturing out onto land, this newly discovered creature had fins that were built for swimming.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="seated man manipulating a stone above a box" src="https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474195/original/file-20220714-9624-3szicz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tom Stewart holds the <em>Qikiqtania</em> fossil.</span>
<span class="attribution"><span class="source">Stephanie Sang</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In March 2020, I was at The University of Chicago and a member of biologist <a href="https://oba.bsd.uchicago.edu/faculty/neil-h-shubin-phd">Neil Shubin’s</a> lab. I was working with Justin Lemberg, another researcher in our group, to process a fossil that was collected back in 2004 during an expedition to the Canadian Arctic.</p>
<p>From the surface of the rock it was embedded in, we could see fragments of the jaws, about 2 inches long (5 cm) and with pointed teeth. There were also patches of white scales with bumpy texture. The anatomy gave us subtle hints that the fossil was an early tetrapod. But we wanted to see inside the rock.</p>
<p>So we used a technology called CT scanning, which shoots X-rays through the specimen, to look for anything that might be hidden within, out of view. On March 13, we scanned an unassuming piece of rock that had a few scales on top and discovered it contained a complete fin buried inside. Our jaws dropped. A few days later, the lab and campus shut down, and COVID-19 sent us into lockdown.</p>
<h2>The fin revealed</h2>
<p>A fin like this is extremely precious. It can give scientists clues into how early tetrapods were evolving and how they were living hundreds of millions of years ago. For example, based on the shape of certain bones in the skeleton, we can make predictions about whether an animal was swimming or walking. </p>
<p>Although that first scan of the fin was promising, we needed to see the skeleton in high resolution. As soon as we were allowed back on campus, a professor in the university’s department of the geophysical sciences helped us to trim down the block using a rock saw. This made the block more fin, less rock, allowing for a better scan and a closer view of the fin.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/aRCdHHe2yfw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An animation of the pectoral fin of <em>Qikiqtania</em> showing how it was preserved in the rock. Scales are shown in yellow, fin rays in blue, and the endoskeleton in grey. <em>Credit: Tom Stewart</em></span></figcaption>
</figure>
<p>When the dust had cleared and we’d finished analyzing data on the jaws, scales and fin, we realized that this animal was a new species. Not only that, it turns out that this is one of the closest known relatives to limbed vertebrates – those creatures with fingers and toes.</p>
<p>We named it <em>Qikiqtania wakei</em>. Its genus name, pronounced “kick-kiq-tani-ahh,” refers to the Inuktitut words Qikiqtaaluk or Qikiqtani, the traditional name for the <a href="https://en.wikipedia.org/wiki/Qikiqtaaluk_Region">region where the fossil was found</a>. When this fish was alive, many hundreds of millions of years ago, this was a warm environment with rivers and streams. Its species name honors the late <a href="https://www.nytimes.com/2021/05/19/science/david-wake-dead.html">David Wake</a>, a scientist and mentor who inspired so many of us in the field of evolutionary and developmental biology.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qCEYP08Q-bw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An animation of the full skeleton of <em>Qikiqtania</em>. <em>Credit: Tom Stewart</em></span></figcaption>
</figure>
<h2>Skeletons tell how an animal lived</h2>
<p><em>Qikiqtania</em> reveals a lot about a critical period in our lineage’s history. Its scales tell researchers unambiguously that it was living underwater. They show sensory canals that would have allowed the animal to detect the flow of water around its body. Its jaws tell us that it was foraging as a predator, biting and holding onto prey with a series of fangs and drawing food into its mouth by suction.</p>
<p>But it is <em>Qikiqtania</em>’s pectoral fin that is most surprising. It has a humerus bone, just as our upper arm does. But <em>Qikiqtania</em>’s has a very peculiar shape.</p>
<p>Early tetrapods, like <a href="https://shubinlab.uchicago.edu/research-2-2/"><em>Tiktaalik</em></a>, have humeri that possess a prominent ridge on the underside and a characteristic set of bumps, where muscles attach. These bony bumps tell us that early tetrapods were living on the bottom of lakes and streams, using their fins or arms to prop themselves up, first on the ground underwater and later on land.</p>
<p><em>Qikiqtania</em>’s humerus is different. It lacks those trademark ridges and processes. Instead, its humerus is thin and boomerang-shaped, and the rest of the fin is large and paddle-like. This fin was built for swimming.</p>
<p>Whereas other early tetrapods were playing at the water’s edge, learning what land had to offer, <em>Qikiqtania</em> was doing something different. Its humerus is truly unlike any others known. My colleagues and I think it shows that <em>Qikiqtania</em> had turned back from the water’s edge and evolved to live, once again, off the ground and in open water.</p>
<h2>Evolution isn’t a march in one direction</h2>
<p><a href="https://plato.stanford.edu/entries/evolution/">Evolution isn’t a simple, linear process</a>. Although it might seem like early tetrapods were trending inevitably toward life on land, <em>Qikiqtania</em> shows exactly the limitations of such a directional perspective. Evolution didn’t build a ladder towards humans. It’s a complex set of processes that together grow the tangled tree of life. New species form and they diversify. Branches can head off in any number of directions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man standing on rocky flat ground with mountains in the distance" src="https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471997/original/file-20220701-22-xozchf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Neil Shubin, who found the fossil, pointing across the valley to the site where <em>Qikiqtania</em> was discovered on Ellesmere Island.</span>
<span class="attribution"><span class="source">Neil Shubin</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>This fossil is special for so many reasons. It’s not just miraculous that this fish was preserved in rock for hundreds of millions of years before being discovered by scientists in the Arctic, on <a href="https://en.wikipedia.org/wiki/Ellesmere_Island">Ellesmere Island</a>. It’s not just that it’s remarkably complete, with its full anatomy revealed by serendipity at the cusp of a global pandemic. It also provides, for the first time, a glimpse of the broader diversity and range of lifestyles of fishes at the water-to-land transition. It helps researchers see more than a ladder and understand that fascinating, tangled tree.</p>
<h2>Discoveries depend on community</h2>
<p><em>Qikiqtania</em> was found on Inuit land, and it belongs to that community. My colleagues and I were only able to conduct this research because of the generosity and support of individuals in the hamlets of Resolute Bay and Grise Fiord, the Iviq Hunters and Trappers of Grise Fiord, and the Department of Heritage and Culture, Nunavut. To them, on behalf of our entire research team, “nakurmiik.” Thank you. Paleontological expeditions onto their land have truly changed how we understand the history of life on Earth.</p>
<p>COVID-19 kept many paleontologists from traveling and visiting field sites across the world these last few years. We’re eager to return, to visit with old friends and to search again. Who knows what other animals lie hidden, waiting to be discovered inside blocks of unassuming stone.</p><img src="https://counter.theconversation.com/content/186116/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Stewart does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The newly discovered species – Qikiqtania – highlights evolution’s twisty, tangled path.Thomas Stewart, Assistant Professor of Biology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1858282022-07-18T12:27:00Z2022-07-18T12:27:00ZWhen did the first fish live on Earth – and how do scientists figure out the timing?<figure><img src="https://images.theconversation.com/files/471719/original/file-20220629-26-9ob4iv.png?ixlib=rb-1.1.0&rect=0%2C0%2C1280%2C1021&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reconstruction of _Haikouichthys ercaicunensis_ based on fossil evidence.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Haikouichthys_3d.png">Talifero/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>How do you figure out how long ago fish were created? Hundreds of millions of years is a long time ago. – Josh, age 11, Ephrata, Pennsylvania</strong></p>
</blockquote>
<hr>
<p>The <a href="https://doi.org/10.1038/46965">oldest fossils of animals resembling a fish</a> date back between 518 million and 530 million years ago. Discovered in China and called <em>Haikouichthys</em>, these animals were about an inch long (2.5 cm) and had a <a href="https://doi.org/10.1038/nature01264">head with seven to eight slits at its base that looked like gills</a>. They also had a <a href="https://doi.org/10.1038/nature01264">distinct spine surrounded by muscles</a>. </p>
<p>But there are ways <em>Haikouichthys</em> did not resemble any modern fish. For example, <a href="https://www.science.org/content/article/fossils-give-glimpse-old-mother-lamprey">they didn’t have a jaw</a>. Instead, their mouth was a cone-like opening similar to the ones seen in <a href="https://nhpbs.org/wild/Agnatha.asp">modern hagfish and lampreys</a>. They also <a href="https://doi.org/10.1038/nature01264">appear not to have had side fins</a>.</p>
<p>Even though <a href="https://scholar.google.com/citations?hl=en&user=w4GYLBMAAAAJ">scientists like me</a> weren’t around to see for ourselves what was happening on Earth so long ago, we use geologic clues to figure out what animals lived when. Here’s how we sort out very ancient timelines and even put dates on fossils like <em>Haikouichthys</em>.</p>
<h2>Measuring in the millions</h2>
<p>To figure out how long ago fish first appeared on Earth you need a way to measure really, really long time intervals. Clocks measure short intervals, like seconds, minutes and hours. Calendars measure longer intervals, like days, months and years. What can you use to measure millions of years?</p>
<p><a href="https://cosmosmagazine.com/earth/earth-sciences/what-is-radiometric-dating/">Radiometric dating</a> is the method that scientists use to calculate the passage of time in millions of years. To determine the age of rocks and fossils, scientists measure the type of atoms they are made of. </p>
<p>You might know that atoms are the building blocks of <a href="https://theconversation.com/what-do-molecules-look-like-184892">molecules, which make up everything around you</a> – grass, cement, even air. While most atoms are very stable, <a href="https://kids.britannica.com/kids/article/radioactivity/399579">some, called radioactive atoms, are unstable</a>. Over long periods of time, they spontaneously break down into more stable atoms. </p>
<p>Uranium is one of these radioactive atoms. <a href="https://kids.kiddle.co/Uranium">It breaks down very slowly into lead</a>. Both uranium and lead atoms can be found <a href="https://kids.kiddle.co/Pitchblende">naturally in rocks and minerals</a> in very, very low amounts. </p>
<p>Nuclear physicists have calculated that it would take <a href="https://www.livescience.com/39773-facts-about-uranium.html">700 million years for one pound of uranium</a> to break down into half a pound of lead. This rate of decay occurs at such a predictable rate that scientists can use it to calculate fairly accurately how old rocks and fossils are.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo of man in old style dress sitting in front of an elaborate contraption." src="https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=431&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=431&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=431&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=542&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=542&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471720/original/file-20220629-22-xaw89m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=542&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ernest Rutherford at McGill University, 1905.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Ernest_Rutherford_1905.jpg">Unknown, published in 1939 in 'Rutherford: being the life and letters of the Rt. Hon. Lord Rutherford'/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The idea for radiometric dating first occurred to <a href="https://library.si.edu/digital-library/book/radioactivit00ruth">a New Zealand scientist named Ernest Rutherford</a> in 1904. His idea was to measure the number of uranium atoms and lead atoms in a rock and compare them. He predicted that an older rock would have more lead and less uranium than a younger rock would.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph illustrating how proportion of unstable atoms in a substance decreases while the proportion of stable atoms increases over time." src="https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471722/original/file-20220629-22-7oc2sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Unstable atoms turn into stable atoms over time at a steady and predictable pace.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/edu/learning/player/lesson15/l15_la1.html">NOAA</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.pbs.org/wgbh/aso/databank/entries/do07ra.html">American scientist Bertram Boltwood</a> put Rutherford’s idea to the test, <a href="https://www.lindahall.org/about/news/scientist-of-the-day/bertram-boltwood">measuring the amount of uranium and lead in different rocks</a> collected from all over the world. </p>
<p>Once a rock is formed, no new elements are added to it. So scientists can calculate how much uranium the rock started with by adding what’s left to the amount of lead that’s there now, thanks to the radioactive decay process. Then, because they know exactly how long it takes for uranium to break down into lead, they can figure out the age of the rock. Boltwood proved that Rutherford’s idea worked, establishing the field of radiometric dating in 1907.</p>
<h2>The making of the <em>Haikouichthys</em> fossil</h2>
<p><a href="https://education.nationalgeographic.org/resource/fossil">Fossils are rocks</a>. So scientists can use radiometric dating to estimate how long ago the organisms that left the fossil imprint lived on Earth. </p>
<p>Animals leave fossil imprints only under special circumstances. In order for the <em>Haikouichthys</em> to leave fossils, their dead bodies would have had to sink to the bottom of the water and be covered with sediments before microorganisms could decompose them. Then, minerals in the sediments would have seeped into the <em>Haikouichthys</em> for their remains to become fossilized. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up photograph of a Haikouichthys fossil with 'eye' and 'V shaped myomere' labeled." src="https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=273&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=273&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=273&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=343&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=343&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472572/original/file-20220705-4393-thhnx8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=343&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A nearly complete specimen of <em>Haikouichthys</em> with the eye and zigzag-shaped muscle fibers called myomeres visible. This is one of many <em>Haikouichthys</em> fossils discovered in China.</span>
<span class="attribution"><span class="source">Dr. and Prof. Degan Shu, Shannxi Key Laborotory of Early Life and Envionment Department of Geology, Northwest University</span></span>
</figcaption>
</figure>
<p>Radiometric dating of <em>Haikouichthys</em> fossils suggests these animals were <a href="https://doi.org/10.1038/46965">swimming in Earth’s waters between 518 million and 530 million years ago</a> – and possibly longer. </p>
<h2>Earth’s age as a 24-hour day</h2>
<p>Scientists, using radiometric dating, <a href="https://education.nationalgeographic.org/resource/how-did-scientists-calculate-age-earth">estimate the Earth itself is 4.5 billion years old</a>. For a long time on Earth, there was no life at all. Then microorganisms like bacteria showed up. It’s only relatively recently that plants and animals began living on Earth.</p>
<p>In fact, if you think of Earth’s age until now as a 24-hour day, it turns out <em>Haikouichthys</em> lived 2 hours and 45 minutes before the end of the day. <a href="https://australian.museum/learn/science/human-evolution/hominid-and-hominin-whats-the-difference/">Humanlike animals</a> appeared even more recently on Earth – about <a href="https://www.smithsonianmag.com/science-nature/the-human-familys-earliest-ancestors-7372974/">5 million to 7 million years ago </a> – only a few minutes before the end of the hypothetical day. </p>
<p>Whether the <em>Haikouichthys</em> was the first fish or not remains controversial. There are very few other fishlike fossils from the same time period. But paleontologists keep digging. Who knows, maybe in a few years they will discover an even older fishlike animal that will dethrone <em>Haikouichthys</em> as the oldest fishlike creature.</p>
<hr>
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<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/185828/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Isaac Skromne receives funding from National Science Foundation and National Institute of Health. </span></em></p>A biologist explains how researchers nail down the age of ancient fossils thanks to a physical process called radioactive decay.Isaac Skromne, Assistant Professor of Biology, University of RichmondLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1828412022-06-20T12:29:50Z2022-06-20T12:29:50ZMillions of years ago, the megalodon ruled the oceans – why did it disappear?<figure><img src="https://images.theconversation.com/files/466658/original/file-20220601-48845-thu3o5.jpg?ixlib=rb-1.1.0&rect=35%2C0%2C4000%2C2694&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Roaming the ancient seas eons ago, the megalodon shark eviscerated its prey with jaws that were 10 feet wide.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/megalodon-scene-3d-illustration-royalty-free-image/1004792742?adppopup=true">Warpaintcobra/iStock via Getty Images Plus</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>When did the megalodon shark go extinct, and why? – Landon, age 10</strong></p>
</blockquote>
<hr>
<p>Imagine traveling back in time and observing the oceans of 5 million years ago. </p>
<p>As you stand on an ancient shoreline, you see several small whales in the distance, gliding along the surface of an ancient sea.</p>
<p>Suddenly, and without warning, an enormous creature erupts out of the depths. </p>
<p>With its massive jaws, the monster crushes one of the whales and drags it down into the deep. Large chunks of the body are ripped off and swallowed whole. The rest of the whales scatter.</p>
<p>You have just witnessed mealtime for megalodon – formally known as <em><a href="https://www.howtopronounce.com/otodus-megalodon">Otodus megalodon</a></em> – the largest shark ever. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="In one hand rests an enormous tooth from a megalodon; in the other hand, two teeth from a great white shark. The megalodon tooth is about six times as large as those of the great white." src="https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466672/original/file-20220601-48323-58vfyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At left, a megalodon tooth; at right, for comparison, two teeth from a great white shark.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/prehistoric-megalodon-shark-tooth-and-two-great-royalty-free-image/1294765101">Mark Kostich/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>About the megalodon</h2>
<p><a href="https://case.fiu.edu/about/directory/profiles/heithaus-michael.html">As a scientist</a> who studies sharks and other ocean species, I am fascinated by the awesome marine predators that have appeared and disappeared through the eons. </p>
<p>That includes huge swimming reptiles like <a href="https://www.kidsnews.com.au/animals/britains-largest-ichthyosaur-skeleton-excavated-in-england/news-story/57f2dcf393250b16f27b75ccbb1ca1a2">ichthyosaurs</a>, <a href="https://theconversation.com/plesiosaurs-pliosaurs-hybodonts-looking-back-at-three-prehistoric-predators-of-the-jurassic-seas-174828">plesiosaurs</a> and the <a href="https://www.livescience.com/mosasaurus-mosasaur.html">mosasaurs</a>. These incredible predators lived during the time of the dinosaurs; megalodon would not appear for another 50 million years. </p>
<p>But when it did arrive on the scene, about 15 million to 20 million years ago, the megalodon must have been an incredible sight. </p>
<p>A fully grown individual weighed about 50 metric tons – that’s more than 110,000 pounds (50,000 kilograms) – and was 50 to 60 feet long (15 to 18 meters). This animal was longer than a school bus and as heavy as a railroad car!</p>
<p>Its jaws were up to 10 feet (3 meters) wide, the teeth up to 7 inches (17.8 centimeters) long and <a href="https://oceanconservancy.org/blog/2020/08/24/7-mega-wild-facts-megalodon/#:%7E:text=With%20a%20jaw%20estimated%20to,40%2C000%20pounds%20per%20square%20inch.">the bite force</a> was 40,000 pounds per square inch (2,800 kilograms per square centimeter). </p>
<p>Not surprisingly, megalodons ate big prey. Scientists know this because they’ve found chips of megalodon teeth embedded in the bones of large marine animals. On the menu, along with whales: large fish, seals, sea lions, dolphins and other sharks. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&rect=44%2C53%2C5946%2C2937&q=45&auto=format&w=1000&fit=clip"><img alt="An artist's conception of a megalodon shark, with black eyes and a mouth wide open, chasing a pod of striped dolphins." src="https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&rect=44%2C53%2C5946%2C2937&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466458/original/file-20220531-48845-gffx97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An artist’s vision of what megalodon might have looked like. Megalodon was found in the warm ocean waters of the tropics and subtropics. Its teeth have been found on every continent except Antarctica.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/megalodon-attack-royalty-free-image/481819827">Corey Ford/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Are scientists sure megalodon is extinct?</h2>
<p>Internet rumors persist that modern-day megalodons exist – that they still swim around in today’s oceans. </p>
<p>But that’s not true. Megalodons are extinct. They died out about 3.5 million years ago. </p>
<p>And scientists know this because, once again, they looked at the teeth. All sharks – including megalodons – produce and ultimately lose tens of thousands of teeth throughout their lives.</p>
<p>That means lots of those lost megalodon teeth <a href="https://science.lovetoknow.com/understanding-science/explaining-fossils-kids">are around as fossils</a>. Some are found at the bottom of the ocean; others <a href="https://www.greatyarmouthmercury.co.uk/news/boy-finds-rare-megalon-tooth-bawdsey-beach-8940068">washed up on shore</a>. </p>
<p>But nobody has ever found a megalodon tooth that’s less than <a href="https://earthathome.org/quick-faqs/how-do-scientists-date-rocks-and-fossils/">3.5 million years old</a>. That’s one of the reasons scientists believe megalodon went extinct then.</p>
<p>What’s more, megalodons spent much of their time relatively close to shore, a place where they easily found prey. </p>
<p>So if megalodons still existed, people would certainly have seen them. They were way too big to miss; we would have lots of photographs and videos. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/BTPcq2HczVY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Watch this PBS Eons video and learn more about the megalodon shark.</span></figcaption>
</figure>
<h2>Why megalodon disappeared</h2>
<p>It probably wasn’t one single thing that led to the extinction of this amazing megapredator, but a complex mix of challenges. </p>
<p>First, the climate dramatically changed. Global water temperature dropped; that reduced the area where megalodon, a warm-water shark, could thrive. </p>
<p>Second, because of the changing climate, entire species that megalodon preyed upon vanished forever. </p>
<p>At the same time, competitors helped push megalodon to extinction – that includes the <a href="https://www.livescience.com/27338-great-white-sharks.html">great white shark</a>. Even though they were only one-third the size of megalodons, the great whites probably ate some of the same prey. </p>
<p>Then there were <a href="https://www.earthtouchnews.com/discoveries/fossils/giant-killer-sperm-whales-once-cruised-australias-waters-and-we-have-a-massive-tooth-to-prove-it/">killer sperm whales</a>, a now-extinct type of sperm whale. They grew as large as megalodon and had even bigger teeth. They were also warmblooded; that meant they enjoyed an expanded habitat, because living in cold waters wasn’t a problem. </p>
<p>Killer sperm whales probably traveled in groups, so they had an advantage when encountering a megalodon, which probably hunted alone. </p>
<p>The cooling seas, the disappearance of prey and the competition – it was all too much for the megalodon. </p>
<p>And that’s why you’ll never find a modern-day megalodon tooth.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/rThDFJFaRow?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">From NatGeo Kids: What it’s like to be a marine biologist.</span></figcaption>
</figure>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/182841/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Heithaus does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A terrifying sight in ancient waters, the megalodon shark was once the most feared creature in the sea.Michael Heithaus, Executive Dean of the College of Arts, Sciences & Education and Professor of Biological Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1849422022-06-16T19:54:25Z2022-06-16T19:54:25ZNew Zealand should celebrate its remarkable prehistoric past with national fossil emblems – have your say!<figure><img src="https://images.theconversation.com/files/468888/original/file-20220615-19-d579ne.jpg?ixlib=rb-1.1.0&rect=49%2C0%2C5472%2C3604&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Trilobites similar to those above have been found in 505 million-year-old rocks in New Zealand.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>It’s not often New Zealanders admit Australia is onto a good thing. Our long-running trans-Tasman rivalry usually revolves around accusing Australians of stealing national cultural icons like Phar Lap, Pavlova or Crowded House.</p>
<p>But I have to admit that when it comes to championing palaeontology (the study of fossils and what they can teach us about our biological heritage), the Australians have a good thing going.</p>
<p>Taking an idea that originated in America, many Australian states in recent decades have started <a href="https://theconversation.com/australia-needs-more-state-fossil-emblems-but-let-the-public-decide-46930">adopting fossil emblems</a> (alongside animal, floral, marine and mineral ones) that epitomise the natural history of each region. </p>
<p>In turn, these emblems can help promote fossil tourism, educational outreach and awareness of the need for fossil protection strategies.</p>
<p>Western Australia chose the 380 million-year-old Devonian fish <em>Mcnamaraspis kaprios</em>, while New South Wales picked a similarly aged fish, <a href="https://www.resourcesandgeoscience.nsw.gov.au/miners-and-explorers_old/geoscience-information_old/nsw-state-emblems/nsw-state-fossil-emblem"><em>Mandageria fairfaxi</em></a>. South Australia adopted the 550 million-year-old <a href="https://www.abc.net.au/news/2017-02-15/reg-sprigg-recognised-honoured-with-sa-fossil-emblem-spriggina/8271586"><em>Spriggina floundersi</em></a> from the dawn of complex life – the first animal in the fossil record whose left and right sides mirrored each other, like ours do today. </p>
<p>The Australian Capital Territory picked the 545 million-year-old brachiopod <a href="https://artsandculture.google.com/story/a-c-t-fossil-emblem/twKCTqZZczzjKA"><em>Atrypa duntroonensis</em></a>, while a public vote in Victoria chose the 125 million-year-old giant amphibian <a href="https://museumsvictoria.com.au/melbournemuseum/state-fossil-emblem/"><em>Koolasuchus cleelandi</em></a>. Queensland is currently holding a public vote to pick an emblem from <a href="https://campaigns.premiers.qld.gov.au/fossilemblem/">12 candidates</a> that include dinosaurs, giant marine reptiles, an amphibian, a crocodile, a <a href="https://australian.museum/learn/species-identification/ask-an-expert/what-is-a-monotreme/">monotreme</a>, a plant and a sea lily.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469095/original/file-20220615-12840-wopa3j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Skull of a shark-toothed dolphin. This large predator lived about 25 million years ago in what is now modern-day southern New Zealand.</span>
<span class="attribution"><span class="source">Mike Dickison/Wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Aotearoa’s rich fossil record</h2>
<p>Aotearoa New Zealand also has a rich fossil record that palaeontologists have used to unlock the evolution of our taonga (treasured) species and their unique whakapapa (lineage), in some cases stretching back tens to hundreds of millions of years. </p>
<p>In spite of this, there’s a distinct shortfall in palaeontological expertise and funding, which is affecting our ability to study and protect the local fossil record.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-did-ancient-moa-survive-the-ice-age-and-what-can-they-teach-us-about-modern-climate-change-183350">How did ancient moa survive the ice age – and what can they teach us about modern climate change?</a>
</strong>
</em>
</p>
<hr>
<p>Nonetheless, New Zealand’s fossils have captured the public imagination, such as the recently discovered 16-19 million-year-old giant Catriona’s shelduck (<a href="https://nzbirdsonline.org.nz/species/catrionas-shelduck"><em>Miotadorna catrionae</em></a>) from St Bathans. Fossils can also inspire future generations through interactive museum displays, outreach and volunteering on fossil digs. </p>
<p><a href="https://www.sciencelearn.org.nz/search?term=fossil">Educational resources</a> can be developed around our unique fossils to teach young New Zealanders how plants and animals evolved in response to the country’s dynamic geological and climatic history. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468895/original/file-20220615-14-zrdu9m.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artist’s impression of <em>Kaiwhekea katiki</em> to scale. The near-complete skeleton of this 75 million-year-old plesiosaur can be seen at Otago Museum.</span>
<span class="attribution"><span class="source">Wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Fossil tourism</h2>
<p>Emblems can also help teach us about the plight and importance of fossils. Newly exposed sites are not being excavated by experts, while other sites are eroding before our eyes. The potential information those sites hold is lost. </p>
<p>While fossil collection by amateurs provides some information, data retention is often substandard, and amateur collection can destroy small sensitive sites. Numerous moa bones, often illegally collected, still come up for sale despite the best efforts to <a href="https://www.rnz.co.nz/news/political/420317/trade-in-moa-bones-would-be-banned-under-proposed-new-rules">stop this practice</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-new-method-of-extracting-ancient-dna-from-tiny-bones-reveals-the-hidden-evolutionary-history-of-new-zealand-geckos-180327">A new method of extracting ancient DNA from tiny bones reveals the hidden evolutionary history of New Zealand geckos</a>
</strong>
</em>
</p>
<hr>
<p>In a post-pandemic world, promoting sustainable tourism is more important than ever. Many regions are uniquely suited to fossil tourism, such as <a href="https://www.waitomocaves.com/">Waitomo</a> and the <a href="https://www.oparara.co.nz/history-of-the-oparara">West Coast</a>. North Otago is already home to the <a href="https://www.whitestonegeopark.nz/">Waitaki Whitestone Geopark</a>, which promotes the geological and fossil history of the region. </p>
<p>Fossil tourism could also be developed at <a href="https://theconversation.com/proposal-to-mine-fossil-rich-site-in-new-zealand-sparks-campaign-to-protect-it-118505">Foulden Maar</a>, a 23 million-year-old lake deposit near Middlemarch in Central Otago, which the public fought to project from mining. It could house a museum and research facilities, and offer opportunities for people to collect fossils for themselves (as happens at <a href="https://www.kronosauruskorner.com.au/">Kronosaurus Korner</a> in Queensland) or volunteer on digs (as they can at the <a href="https://www.australianageofdinosaurs.com/">Australian Age of Dinosaurs</a>).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468893/original/file-20220615-12-7m0rlx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Skull of the mosasaur <em>Prognathodon overtoni</em> that Joan Wiffen discovered. This fearsome predator ruled the oceans of the Late Cretaceous.</span>
<span class="attribution"><span class="source">Lloyd Homer/GNS Science</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Time to choose</h2>
<p>So, what should New Zealanders choose for their fossil emblem? Should we pick something flashy like the pouakai/<a href="https://nzbirdsonline.org.nz/species/haasts-eagle">Haast’s eagle</a> (<em>Aquila moorei</em>) whose ancestor, the smallest eagle in the world, arrived in Aotearoa only about 2.5 million years ago and rapidly evolved into the world’s largest?</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=775&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=775&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=775&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=974&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=974&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468894/original/file-20220615-15-mupsdz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=974&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artist’s reconstruction of pouakai/Haast’s eagle (<em>Aquila moorei</em>), the largest eagle in the world, <strong>which</strong> went extinct only 500-600 years ago.</span>
<span class="attribution"><span class="source">Paul Martinson/Te Papa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>What about the 75 million-year-old <a href="https://www.otago.ac.nz/geology/research/paleontology/kaiwhekea-katiki.html">plesiosaur</a> <em>Kaiwhekea katiki</em> or the <a href="https://www.otago.ac.nz/geology/research/paleontology/squalodontidae.html">shark-toothed dolphin</a> that capture my children’s attention?</p>
<p>We could agree that size does matter and choose the 55-60 million-year-old <a href="https://nzbirdsonline.org.nz/species/bices-penguin">giant Bice penguin</a> (<em>Kumimanu biceae</em>) or moa nunui/<a href="https://nzbirdsonline.org.nz/species/south-island-giant-moa">South Island giant moa</a> (<em>Dinornis robustus</em>). At the other end of the scale, how about the smallest fossils like 505 million-year-old <a href="https://teara.govt.nz/en/photograph/8297/trilobite-rock">trilobites</a>, some of our oldest fossils?</p>
<p>Should we consider historical value, like the first theropod dinosaur or one of the mosasaurs (such as <em>Prognathodon overtoni</em>) that pioneering fossil hunter <a href="https://teara.govt.nz/en/biographies/6w4/wiffen-joan">Joan Wiffen</a> discovered? Or should scientific value prevail, like the living pūpū whakarongotaua/<a href="https://en.wikipedia.org/wiki/Placostylus_ambagiosus">flax snail</a> (<em>Placostylus ambagiosus</em>), whose abundant fossil shells are teaching us a lot about the impacts of climate change and human settlement?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/proposal-to-mine-fossil-rich-site-in-new-zealand-sparks-campaign-to-protect-it-118505">Proposal to mine fossil-rich site in New Zealand sparks campaign to protect it</a>
</strong>
</em>
</p>
<hr>
<p>I’m forming a committee of palaeontologists from across New Zealand to decide on a shortlist to put to a public vote. We would welcome input about what fossils to consider, whether we should have a single emblem representing New Zealand, or regional emblems, and even a yearly competition like the sometimes controversial <a href="https://www.birdoftheyear.org.nz/">Bird of the Year</a>.</p>
<p>So get your iwi, whanau, school and local museum involved, lobby your local politicians and let us know what you think at <em>nzfossilemblem@otago.ac.nz</em></p><img src="https://counter.theconversation.com/content/184942/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p>Australia has them, so why doesn’t New Zealand have national or regional fossil emblems? A campaign to change that kicks off today.Nic Rawlence, Senior Lecturer in Ancient DNA, University of OtagoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1835692022-05-25T14:38:04Z2022-05-25T14:38:04ZWhy a 110-million-year-old raptor skeleton should never have been sold at auction for over US$12M<figure><img src="https://images.theconversation.com/files/465147/original/file-20220524-20-vcbpmb.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C5760%2C3802&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A skeleton of an Allosaurus on display at Drouot auction house in Paris, in October 2020. It sold for three million euros, double the asking price.</span> <span class="attribution"><span class="source">(AP Photo/Thibault Camus)</span></span></figcaption></figure><p>In mid-May, Christie’s auction house in New York sold a raptor skeleton <a href="https://www.livescience.com/deinonychus-inspired-jurassic-park-dinosaur-auctioned">(<em>Deinonychus</em>) for US$12.4 million</a>. This represents a failure to protect and share our natural history with everyone. </p>
<p>We are paleontologists and represent the <a href="https://www.vertpaleo.org">Society of Vertebrate Paleontology</a>, a group of 2,000 scientists, students and museum professionals around the world. We are promoting awareness of the problems that high-profile auctions of vertebrate fossils cause, and why we think they shouldn’t happen.</p>
<p>Fossils are fascinating and beautiful objects. They provide a glimpse into a past substantially different from our present. We love seeing them come to life in <a href="https://ew.com/books/jurassic-world-expert-picks-best-dinosaur-movies/">movies</a>. As paleontologists, we share the wonder, but when significant fossil specimens are held by individuals and not public institutions, society loses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a large dinosaur on display at a museum with visitors around it" src="https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465134/original/file-20220524-23-ze403w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dinosaur skeletons provide scientific knowledge and educate the public about the history and life of our planet.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Private ownership, public losses</h2>
<p>Loss of high-profile dinosaur skeletons clearly hurts both science and the public. <a href="https://www.aaps-journal.org/International-Fossil-Laws.html">Some countries</a> have a sense of “cultural patrimony” that includes not only cultural heritage, but natural heritage as well. This informs their laws, and prevents fossil sales and the unauthorized removal of fossils from their countries. When a fossil is sold, this heritage is removed from people in that country without consent. </p>
<p>When people are permitted access to private fossil collections, they are often from the purchaser’s country and not from the specimen’s country of origin, leaving local people cut off from seeing the fossil and learning about their own natural heritage. Not surprisingly, laws protecting cultural and natural heritage are often strongest in countries who have suffered the greatest loss of this heritage, <a href="http://ojs-igl.unam.mx/index.php/Paleontologia/article/view/635">like Mexico</a>.</p>
<p>How much have the United States and other countries without legal protections in place lost through fossil auctions? We are only just beginning to understand. Of the known specimens of <em>Tyrannosaurus rex</em>, <a href="https://www.businessinsider.com/christies-deinonychus-fossils-dinosaurs-wealthy-private-buyers-damaging-science-2022-5?op=1">only 55 per cent are in collections in the public trust — and the remainder are in private hands</a>.</p>
<p>The scientific community also loses. Specimens complete enough to be sold at legal auctions are often of significant scientific value, but may have been prepared in ways that inflate esthetic value at the expense of long-term stability.</p>
<p>Benevolent purchasers might want scientists to study their specimens, but there is no guarantee that <a href="http://collections.paleo.amnh.org/21/data-and-data-management">primary data</a> is recorded, rendering the fossil less meaningful for scientific research. Casts and CT scans allow some work to continue, but techniques that require examination of the original bone cannot be used, nor can new hypotheses be tested.</p>
<p>Even when provenance — the documentation of a fossil’s discovery and acquisition — is preserved, specimens held privately but made available to researchers have later been removed from access, and in some cases have disappeared after the death of their owners. This may have been the case with <a href="https://doi.org/10.1038/357006b0">one of 12 known specimens of the enigmatic transitional bird <em>Archaeopteryx</em></a>.</p>
<h2>Market purchases</h2>
<p>Legal fossil auctions help drive <a href="https://www.smithsonianmag.com/science-nature/the-dinosaur-fossil-wars-116496039/">the black market because high prices attract more people to excavate and sell more fossils of all kinds</a>, and try to export them against local laws. When fossils are seen as accessories, investments or interior decor rather than scientific objects that represent the natural heritage of a region, this drives desire for these objects.</p>
<p>While not everyone can afford a <em>Deinonychus</em> skeleton, such sales drive desire for specimens at all economic levels.</p>
<p>One might ask whether museums could just start purchasing scientifically significant fossils to “save” them. After all, collectors and preparators (the scientists who preserve and prepare the specimen) deserve to be paid. However, often it is middlemen, and not the discoverers and landowners, who profit the most from these sales.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a fossil of an Archaeopteryx, a birdlike dinosaur" src="https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=520&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=520&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465136/original/file-20220524-13-ix0av2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=520&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A fossil of an <em>Archaeopteryx</em> disappeared in 1991 after its owner passed away.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Museums, whether public or private, have limited budgets and cannot afford to pay the ever-increasing costs of auctioned specimens. The sum paid for the auctioned raptor would fund the discovery, collection, study, preservation and public exhibit of many more fossils. </p>
<h2>Living room dinosaurs</h2>
<p>We are not arguing that commercial collectors have no role to play, or that no fossils should be sold. However, privately owned dinosaur fossils do not further science or education and such ownership costs the public their access to, and knowledge about, these fossils.</p>
<p>Any time a fossil is sold to a private collector, there are no guarantees that it will remain in its country of origin or that it will be displayed to the public or be available to scientists. There are also no guarantees that it will be maintained and cared for properly, or that data collected with it will be preserved. </p>
<p>These items are not just pretty <a href="https://gizmodo.com/fossil-poaching-and-the-black-market-in-dinosaur-bones-1577785816">cabinet curios</a>, but contain vitally important information about the history and life of our planet. It is up to all of us, not just scientists, to understand the stories they tell us and protect them for future generations. In short, we believe that it is critical to stop auctioning off the natural heritage of the world to the highest bidder.</p><img src="https://counter.theconversation.com/content/183569/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Theodor is the President of the Society of Vertebrate Paleontology. She receives funding from the Natural Sciences and Engineering Research Council of Canada. </span></em></p><p class="fine-print"><em><span>Margaret Lewis is the Vice President and Ethics Officer of the Society of Vertebrate Paleontology. She has received funding from the National Science Foundation and Leakey Foundation.</span></em></p>The sale of fossils at auction houses reflects a problematic trend of privileging profit over knowledge and education.Jessica M. Theodor, Professor of Biological Sciences, University of CalgaryMargaret E. Lewis, Professor, Natural Sciences, Stockton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1834232022-05-24T12:27:00Z2022-05-24T12:27:00ZYorkicystis, the 500 million-year-old relative of starfish that lost its skeleton<figure><img src="https://images.theconversation.com/files/464096/original/file-20220518-21284-9rc32x.jpeg?ixlib=rb-1.1.0&rect=92%2C70%2C1896%2C1273&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reconstruction of the prehistoric *Yorkicystis haefneri* adapted from fossil evidence, created by Hugo Salais (Metazoa Studio).</span> <span class="attribution"><span class="source">Samuel Zamora</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>After four years of digging for fossils in a churchyard in York, Pennsylvania, amateur paleontologist Chris Haefner made an intriguing find. “I knew it was worth keeping,” he said. He posted his discovery on Facebook. </p>
<p>I spotted his post, and realized it was a major discovery: <a href="https://www.researchgate.net/profile/Samuel-Zamora">I study fossil invertebrates</a> at the Spanish Research Council. When I contacted Haefner, he agreed to donate the fossil to London’s Natural History Museum. </p>
<p>Working with colleagues in the U.S. and U.K., we determined that this was a 510 million-year-old relative of today’s starfish and sea urchins. It is highly unique, new to science, and has only a partial skeleton. We named it <em><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2733">Yorkicystis haefneri</a></em>, after its finder. </p>
<p><em>Yorkicystis</em> has revealed new information about how early life was evolving on Earth at a time when most of today’s animal groups first appeared.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Skeleton of a current sea urchin and details of one of its calcite plates. On the right, the microstructure that forms its skeleton, known as a stereome." src="https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=377&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=377&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=377&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464350/original/file-20220519-16763-oyi9h4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sea urchins are among <em>Yorkicystis</em>‘ surviving relatives.</span>
<span class="attribution"><span class="source">Samuel Zamora</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>The Cambrian explosion</h2>
<p><em>Yorkicystis</em> lived during the “Cambrian explosion,” 539 million to 485 million years ago. Before this time, bacteria and other simple microscopic organisms lived alongside <a href="https://ucmp.berkeley.edu/vendian/ediacaran.php">Ediacaran fauna</a>, mysterious, soft-bodied creatures that scientists know little about. </p>
<p>The Cambrian brought a huge proliferation of species that emerged from the seas. They included groups of organisms that would eventually dominate the planet and representatives of most of today’s animal groups.</p>
<p>Within a few million years, complex animals with skeletons and hard shells appeared. Why this happened remains unclear, but <a href="https://doi.org/10.1130/G25094A.1">a major change in ocean chemistry</a>, with a higher concentration of calcium carbonate, likely played a key role.</p>
<p>Echinoderms weren’t the first of these found in the geological record. <a href="https://www.bgs.ac.uk/discovering-geology/fossils-and-geological-time/brachiopods/">Brachiopods</a> – marine animals that lived protected within seashells – predated them. So did <a href="https://www.palaeontologyonline.com/articles/2015/fossil-focus-cambrian-arthropods/">arthropods</a>, a group that had well-formed <a href="https://australian.museum/learn/australia-over-time/fossils/what-are-trilobites/">calcite exoskeletons</a>, including <a href="https://www.britannica.com/animal/trilobite">trilobites</a>.</p>
<p>For context, dinosaurs appeared 294 million years after the dawn of the Cambrian.</p>
<h2>The first echinoderms</h2>
<p>There are more that <a href="https://www.digitalatlasofancientlife.org/learn/echinodermata/">30,000 extinct echinoderm species</a>, but they are very rare in places with exceptional Cambrian preservation, like <a href="https://www.rom.on.ca/en/the-burgess-shale-the-virtual-museum-of-canada">the Burgess Shale</a> in Canada and <a href="https://whc.unesco.org/en/list/1388/">Chengjiang in China</a>. </p>
<p>Some of the first primitive echinoderms were quite different from their present-day relatives, which have five arms extending from the center of their bodies, a structure called “pentamerous symmetry.” </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1005064550146822145"}"></div></p>
<p>Cambrian echinoderms had a wide range of <a href="https://doi.org/10.4202/app.00048.2013">body structures</a>. <a href="https://ucmp.berkeley.edu/echinodermata/eocrinoidea.html">Eocrinoids</a> had vase-shaped bodies protected by geometrically patterned plates and a number of armlike structures. <a href="https://doi.org/10.1669/0883-1351(2001)016%3C0197:TAEDOH%3E2.0.CO;2">Helicoplacoids</a>, shaped like fat cigars, were plated in calcite armor with a “mouth” that spiraled around its body. <a href="https://www.digitalatlasofancientlife.org/learn/echinodermata/fossil-echinoderms/">Blastoid</a> species took various shapes, often resembling exotic flowers.</p>
<p>The Edrioasteroidea looked similar to <a href="https://ucmp.berkeley.edu/echinodermata/edrioasteroidea.html">today’s sea star</a>, and with five arms that radiated from its mouth, it is the organism that <em>Yorkicystis haefneri</em> most resembles. So we <a href="https://doi.org/10.1098/rspb.2021.2733">classified it within this group</a> on the evolutionary tree. </p>
<h2><em>Yorkicystis</em>, the echinoderm without a skeleton</h2>
<p>While many Cambrian organisms formed sophisticated skeletons and defense structures to protect them from predators, <em>Yorkicystis</em> did the opposite. It “demineralized” its skeleton. It was a partially soft animal, with no protection over much of its body. </p>
<p>To understand this organism’s anatomy, we partnered with a paleoillustrator to visualize this creature from the fossil evidence we had. Hugo Salais first modeled each part of the skeleton in 3D and then used that to create a reconstruction, a high-resolution replica. </p>
<p>From this replica, we observed that only its arms, or ambulacra, were calcified, protecting its “food grooves” — its feeding parts, which are yellow in the fossil. A series of plates covered its tentacles and opened and closed during feeding. The rest of its body was soft, represented in the fossil by a dark, carbon-enriched film.</p>
<p>Most present-day echinoderms, which are found from the world’s coastlines to the ocean’s dark abyssal depths, have an internal skeleton. The exceptions are sea cucumbers and some species that live buried beneath the seabed. Their skeletons, like <em>Yorkicystis</em>, are formed by porous calcite plates.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black and white image of six extinct organisms' fossils" src="https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=621&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=621&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=621&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=780&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=780&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464354/original/file-20220519-11071-5mlqtv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=780&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Representatives of Cambrian echinoderms with a mineralized calcite skeleton. A. Ctenocystoid. B. Cincta. C. Helicoplacoid. D. Solute. E. Eocrinoid. F. Edrioasteroid.</span>
<span class="attribution"><span class="source">Samuel Zamora</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Bringing <em>Yorkicystis</em> to life</h2>
<p>As paleontologists, we seek to understand extinct organisms. <em>Yorkicystis</em> presented a major challenge, since no similar animal is known, neither living nor extinct.</p>
<p>Very little is known about why and how some echinoderms lost parts of their skeleton. But advances in molecular biology have revealed that there is <a href="https://doi.org/10.1126/science.1132310">a specific set of genes</a> responsible for the formation of a skeleton in echinoderms. All living echinoderms carry these genes; we assume that extinct groups did, too. </p>
<p>But in <em>Yorkicystis</em>, there is a marked difference between the calcification of its rays, or arms, and the lack of it on the rest of its body. It raises the hypothesis that the genes involved in skeleton formation may have acted independently in different parts of <em>Yorkicystis</em>‘ body. It’s a mystery that only molecular biologists will be able to unravel.</p>
<p>Our studies have allowed us to form some hypotheses about this animal, though many questions remain. We believe that without a skeleton in an important part of its body, <em>Yorkicystis</em> was able to conserve energy for other metabolic processes such as feeding or breathing. It also enhanced flexibility, allowing for more active respiration by means of pumping.</p>
<p>There’s another intriguing possibility: The lack of skeleton might be related to some kind of stinging protection system, like that used by present-day <a href="https://www.mba.ac.uk/fact-sheet-sea-anemones">anemones that paralyze prey</a> with stinging cells on the tentacles that surround their mouths. That question, though, and many others, can’t be answered with just a fossil.</p>
<p>But the amazing discovery of <em>Yorkicystis</em> has provided more insight into a period in divergent evolutionary history at the dawn of the Cambrian explosion, a time when some organisms adopted skeletons to avoid predators – and others adapted in very different ways.</p><img src="https://counter.theconversation.com/content/183423/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samuel Zamora receives funding from the Spanish Ministry of Science,
Innovation and Universities (grant no CGL2017-87631), co-financed
by the European Regional Development Fund and the project
‘Aragosaurus: Recursos Geológicos y Paleoambientales’ (E18_17R)
funded by the Government of Aragon. </span></em></p>The discovery of a unique 510 million-year-old fossil in a Pennsylvania churchyard offers new clues into how early life evolved on Earth.Samuel Zamora, Científico Titular (Paleontólogo), Instituto Geológico y Minero de España (IGME - CSIC)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1810232022-04-27T12:48:12Z2022-04-27T12:48:12ZDoes this dinosaur ‘graveyard’ reveal their final day on Earth? An expert explores the evidence<p>Buried in the rocks in North Dakota lies evidence of the exact day the dinosaurs were obliterated from the planet, some 66 million years ago. That’s the claim of palaeontologist Robert DePalma and colleagues, whose work was captured by the BBC in its recent landmark documentary <a href="https://www.bbc.co.uk/programmes/m0016djt">Dinosaurs: The Final Day with David Attenborough</a>.</p>
<p>For the last ten years, DePalma has focused his work on a <a href="https://en.wikipedia.org/wiki/Tanis_(fossil_site)">fossil rich site</a> – which he has named “Tanis” – in North Dakota’s Hell Creek Formation. And since 2019, he and his colleagues have put forward some very strong claims about what Tanis tells us about the end of the Cretaceous period.</p>
<p>DePalma believes that Tanis is a mass graveyard of creatures killed during the asteroid strike. </p>
<p>There is no doubt that an asteroid led to the <a href="https://www.science.org/doi/full/10.1126/science.aay5055">mass extinction</a> of non-avian dinosaurs – and at least 50% of other species – 66 million years ago. But there has been some controversy around DePalma’s claim that the site documents the very day that the asteroid struck – and reveals direct evidence of the very last dinosaurs on Earth.</p>
<p>So, let’s take a look at what we know about this most important time in our planet’s history – and what remains uncertain.</p>
<h2>The huge asteroid collision</h2>
<p>When the asteroid impact theory was <a href="https://en.wikipedia.org/wiki/Alvarez_hypothesis">first proposed in 1980</a>, there was no crater. The only evidence was two sites with substantial enrichment of iridium – an element that arrives on the Earth’s surface from outer space – in the rocks exactly at the level of the end of the Cretaceous. </p>
<p>Now there are hundreds of places worldwide showing the iridium spike, at what is known as the K-Pg (Cretaceous-Paleogene) boundary, a geological signature in the sediment.</p>
<p>And then in 1991 came the huge breakthrough - the <a href="https://theconversation.com/how-does-an-invisible-underwater-crater-prove-an-asteroid-killed-the-dinosaurs-57711">Chicxulub crater</a> was found in what is now the Yucatán Peninsula in southern Mexico. </p>
<p>At 180km (110 miles) wide, and 20km (12 miles) deep, the crater shows that a huge 10km (six mile) wide asteroid crashed into the sea. Its force was so great, that it unleashed huge tsunami waves, as well as massive amounts of rock debris and <a href="https://theconversation.com/scientists-have-found-dust-from-the-asteroid-that-wiped-out-the-dinosaurs-inside-the-crater-it-left-156232">dust containing iridium</a> into the atmosphere – and also triggered a <a href="https://theconversation.com/revealed-asteroid-that-killed-the-dinosaurs-boiled-earths-atmosphere-36606">powerful heat wave</a>.</p>
<p>Most experts agree that all life within around 1,700km (1,000 miles) of the collision would have been wiped out instantly. </p>
<p>But Tanis was more than 2,800km (or 1,800 miles) away. And up until now, there was no evidence of the very last dinosaurs. So, what’s the basis for DePalma’s groundbreaking revelation that Tanis finally provides the elusive evidence of the dinosaurs’ last day?</p>
<h2>Asteroid evidence at Tanis</h2>
<p>There is little doubt that the Tanis site lies close to the end of the Cretaceous Period, because DePalma has identified the iridium layer immediately above the fossil bed, which places it at the K-Pg boundary.</p>
<p>He has also presented some compelling pieces of evidence that the site marks the exact day the asteroid struck.</p>
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Read more:
<a href="https://theconversation.com/dinosaur-killing-asteroid-struck-at-worst-angle-to-cause-maximum-damage-new-research-139394">Dinosaur-killing asteroid struck at worst angle to cause maximum damage – new research</a>
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<p>First, there are the ancient channels in the sedimentary rocks at Tanis – these are evidence of the huge standing water (or “seiche”) waves which engulfed Tanis. At that time North America was divided by a great seaway that passed close to the Tanis site: the seiche waves would have run up the creeks, and out again, several times, mixing fresh and sea waters to create the waves.</p>
<p>The ground-borne shock waves from the asteriod impact – which caused the devastating water surges – could readily travel through the Earth’s crust from the impact site to Tanis. </p>
<p>When the asteroid crashed into Earth, tiny ejector spherules, glassy beads about 1mm wide, were formed from melted molten rock – and were able to travel up to around 3,200km (2,000 miles) through the atmosphere because they were so light. </p>
<p>Astonishingly, DePalma found these glassy spherules at the site, and also in the gills of sturgeon fossils which occupied the Tanis streams. He believes the spherules were produced by the Chicxulub impact because of their shared chemistry, with some even encapsulating “fragments of the asteroid” itself. If this is true, their occurrence at Tanis would indeed confirm that they mark the actual day of impact, because the spherules would have fallen to the ground within hours of the impact.</p>
<h2>Tanis fossil findings</h2>
<p>From decades of study of the rocks and fossils at <a href="https://en.wikipedia.org/wiki/Hell_Creek_Formation">Hell Creek Formation</a>, we know that Tanis was a warm and wet forest environment, with a thriving ecosystem full of dinosaurs, pterosaurs (flying reptiles), turtles and early mammals. Although they are yet to be described in detail, DePalma and colleagues reveal some incredible new fossils of animals – and he believes they could well have died on the day of the impact itself, due to their location in the doomed Tanis sandbank. </p>
<p>First, there’s an exceptionally <a href="https://www.theguardian.com/science/2022/apr/07/fossil-dinosaur-killed-asteroid-strike-thescelosaurus-north-dakota-extinction?fr=operanews">preserved leg</a> of the herbivorous dinosaur <em>Thescelosaurus</em>, which shows not only the bones, but also skin and other soft tissues. </p>
<p>But that’s not all. There is a pterosaur baby, just about to hatch from its egg – and, some incredibly well preserved <em>Triceratops</em> skin, which is an extremely unusual find.</p>
<p>Even more astonishingly, there is a turtle impaled by a stick, which DePalma believes could be evidence of a tragic death in the turbulent seiche waves set off by the impact.</p>
<p>DePalma’s final claim is that the impact, and final day, <a href="https://www.nature.com/articles/s41598-021-03232-9">occurred in May</a>, based on microscopic and geochemical analysis of growth rings in the fin spines of the fossil sturgeon. The bones show seasonal banding – where bone grows rapidly when food is abundant and slowly when conditions are poorer, so often summers are shown by a wide pale band and winters by a narrow dark band. The last banding cycle in the sturgeon confirms it died in May. And a <a href="https://www.nature.com/articles/s41586-022-04446-1">further study</a> this year has confirmed this.</p>
<h2>So, why the uncertainty?</h2>
<p>There is no doubt that DePalma’s claims <a href="https://www.science.org/doi/epdf/10.1126/science.364.6435.10">have been controversial</a> since they were first presented to the world in 2019 – probably because the announcement was in the <a href="https://www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died">New Yorker magazine</a> rather than a peer-reviewed journal.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fish-bones-and-water-lilies-help-pin-down-the-month-the-dinosaurs-died-175459">Fish bones and water lilies help pin down the month the dinosaurs died</a>
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</em>
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<p>But the findings about seiche waves were then published in an <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1817407116">academic paper </a> only a month later, and most geologists were convinced.</p>
<p>It is true that the fossils, which were revealed for the first time in the BBC documentary – along with the evidence that the glass spherules at Tanis are linked to the Chicxulub impact – have yet to be published in scientific journals, where they would be subject to peer review.</p>
<p>But, experience shows that most of what DePalma has revealed in the past has been backed up subsequently by peer-reviewed papers. </p>
<p>Over the past two years I worked as one of the independent scientific consultants to the BBC, verifying the claims, as they made the documentary. Both I and my colleagues, and many other experts, are satisfied that the Tanis site probably does reveal the very last day of the non-avian dinosaurs.</p>
<p>And of course, as we all know, the impact of the asteriod went far beyond that one day. It led to a freezing dark planet, on a global scale, lasting for days or maybe weeks – and, from this mass extinction worldwide, the age of the mammals emerged.</p><img src="https://counter.theconversation.com/content/181023/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael J. Benton receives funding from Natural Environment Research Council, Leverhulme Trust, European Research Council.</span></em></p>A recent BBC documentary examined fossils thought to have been made when an asteroid wiped out the dinosaurs.Michael J. Benton, Professor of Vertebrate Palaeontology, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1781942022-03-09T16:23:14Z2022-03-09T16:23:14ZWe discovered how the largest dinosaurs walked – and it was more like hippos than elephants<figure><img src="https://images.theconversation.com/files/450781/original/file-20220308-21-iec6t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendering-walking-alamosaurus-1435978490">Kostiantyn Ivanyshen/shutterstock</a></span></figcaption></figure><p>While our knowledge of dinosaurs and other extinct animals has dramatically increased during the last couple of decades, their gaits – the order and timing of how animals move their legs – have remained a blind spot. </p>
<p>We are particularly interested in the giant long-necked sauropod dinosaurs, which include the largest animals that walked the earth, including such famous species as <em>Diplodocus</em>, <em>Brontosaurus</em> and <em>Brachiosaurus</em>. How did these giants move? What role did efficiency and stability play during their locomotion? </p>
<p>Those questions have not been easy to answer. The problem is that skeletons are the remains of deceased animals and don’t preserve motion. So reconstructing gaits based on fossilised bones can only indirectly provide clues, and are far from conclusive. </p>
<h2>Investigating gait from tracks</h2>
<p>As it happens, there is another type of fossil that records the activity of an animal when it was alive, and they are known as fossil trackways. But until now, extracting gait information about extinct dinosaurs from these footprints has proved difficult. </p>
<p><a href="https://www.google.co.uk/books/edition/Dinosaur_Tracks/EzI_DAAAQBAJ?hl=en&gbpv=1&dq=dinosaur+tracks+the+next+steps+stevens&pg=PA227&printsec=frontcover">A 2016 study</a> demonstrated that two animals of different sizes and using different gaits could produce identical track patterns. This means that to identify gait from the tracks we would need to know the trunk length of the animal (distance from hip to shoulder). Unfortunately it could not be accurately estimated from tracks so we were left with too many unknowns.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-social-species-newly-discovered-fossils-show-early-dinosaurs-lived-in-herds-170245">A social species? Newly discovered fossils show early dinosaurs lived in herds</a>
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<p>But one important aspect had not yet been taken into account – the variation along a set of tracks caused by small changes in speed. In <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(22)00234-2">our new study</a>, we used this variation to present a new method to use tracks to work out which gait had been used. </p>
<p>Obviously the trunk length of an animal cannot change as it walks – so, we can therefore measure the trunk length from the tracks at many different points along it, while each time assuming a different gait. The gait which produces the most consistent trunk length along the tracks can be assumed to be the correct one.</p>
<figure class="align-center ">
<img alt="Large footprints on a track" src="https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450776/original/file-20220308-17665-8bh42z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sauropod tracks from Utah.</span>
<span class="attribution"><span class="source">Jens Lallensack</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>It all made perfect mathematical sense. All we needed to do was make sure our new method worked when applied to the tracks of modern animals, including three dogs, two horses and an elephant. In each case, the method produced gratifyingly accurate estimates of the animals’ gaits.</p>
<h2>How dinosaurs moved</h2>
<p>So, for the first time we had developed a way to study gaits of the past. We applied the method to three fossilised tracks of giant sauropods from the Early Cretaceous period of Arkansas, in the US – the largest of which had footprint lengths of 85cm. </p>
<p>The results were really surprising. <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078733">Previous studies</a> suggested that sauropods might have walked in a pace gait (similar to a camel) or a singlefoot walk (similar to a slow moving horse). But we expected that sauropod gaits would resemble those of elephants, as they are the largest land animals alive today. </p>
<p>Elephants employ lateral couplets gaits – they tend to move the fore and hind limb of the same body-side together, like in the animation below. They therefore fall in between the pace gait (the extreme of a lateral couplets gait where hind and fore limb of one body side move exactly in sync) and the singlefoot gait (where the time lag between all limb movements is exactly equal).</p>
<figure class="align-center ">
<img alt="Animation showing how animal legs move using a lateral couplet gait, where limbs of the same side move together" src="https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450777/original/file-20220308-13-uti16o.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The lateral couplets gait, seen in animals such as elephants.</span>
<span class="attribution"><span class="source">Jens Lallensack</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our new method, however, indicates that all three sauropods we studied via tracks had walked in a diagonal couplets gait, where they move the limbs of the opposite body-side together. The extreme in this gait is called a trot (the diagonal pair moves exactly in sync). So, to our surprise sauropods did the opposite of what we see in elephants. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/2ypz_QvxMx4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>How can this difference be explained? Well, Cretaceous sauropods do differ from elephants in one important aspect – they are much wider. The tracks we studied are especially broad (or wide-gauged), with left and right tracks spaced well apart from each other. </p>
<p>Elephants, in contrast, set one foot almost in front of the other, forming a narrow path. This has consequences for the gait. An elephant only needs to shift its body mass slightly to one side in order to swing both legs of the other side forward together. A wide-gauged sauropod, however, would have needed to drastically sway its body towards one side to achieve the same. </p>
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Read more:
<a href="https://theconversation.com/dinosaur-embryo-discovery-rare-fossil-suggests-dinosaurs-had-similar-pre-hatching-posture-to-modern-birds-174040">Dinosaur embryo discovery: rare fossil suggests dinosaurs had similar pre-hatching posture to modern birds</a>
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<p>So, the diagonal couplets gait assured that the sauropods always had at least one foot on the ground on either side of the body, avoiding such swaying from left to right. Stability therefore seems to have played a major role in how the largest creatures ever to have roamed this planet walked.</p>
<p>Interestingly, almost all large modern mammals show very narrow tracks, in combination with lateral couplets gaits. But the wide-tracked hippopotamus, in contrast, uses a diagonal couplets gait (moving limbs of the opposite body side together) just as we estimated for wide-tracked sauropods. So while it’s easy to assume that because elephants are the largest animals on land today, large land animals of the past must have moved like them, it appears that this was not the case.</p><img src="https://counter.theconversation.com/content/178194/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Falkingham works for Liverpool John Moores University, UK.</span></em></p><p class="fine-print"><em><span>Jens N. Lallensack receives funding from the German science foundation</span></em></p>Thanks to our new technique using fossilised tracks, we have been able to learn more about the locomotion of the largest creatures ever to have roamed this planet.Peter Falkingham, Reader in Vertebrate Biology, Liverpool John Moores UniversityJens N. Lallensack, Postdoctoral Research Fellow in Palaeontology, Liverpool John Moores UniversityLicensed as Creative Commons – attribution, no derivatives.