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Found: the dinosaur that survived mass extinction

Good times, bad times, you know I had my share. epsos, CC BY

Found: the dinosaur that survived mass extinction

A dinosaur has been found in Argentina which may have lasted beyond an extinction event that wiped out the rest of its family. The new species has been named Leinkupal laticauda, which in the language of the Native American Mapuche nation of northwestern Patagonia means “vanishing family”, because it was truly the last of its kind.

Mass-extinction events are nature’s way of separating the wheat from the chaff. Those species that cannot adapt to changing conditions are lost forever. New species evolve into the spaces left by the losers, and the game of life begins again with new players.

In their 180 million years on Earth, dinosaurs suffered multiple mass extinctions. The final one saw the combined effects of an asteroid impact and massive volcanism which caused rapid changes to the environment and nearly wiped them out completely about 66m years ago, leaving just their bird descendants remaining.

The fossil and geological records from these times can give us insight into what may have caused their extinction. They put in perspective the catastrophic events that punctuated the evolutionary history of these beasts.

Giant sauropods are among the most iconic dinosaurs. These leaf-eating dinosaurs were the biggest animals to ever walk on Earth. But about 145 million years ago, many of them succummbed to the Jurassic/Cretaceuous boundary event in a mass extinction that severly affected much of life on land and sea. There is still some debate as to what the cause of this may have been, but strong contenders include a triple whammy of meteor impacts, massive sea-level changes and environmental disturbances, and large-scale volcanism in the Pacific.

It was previously thought that diplodocids, a group of sauropods with narrow teeth to which Leinkupal laticauda belongs, went extinct at this boundary. Their diversity was declining and it seemed as if the extinction event was the last nail in their over-sized coffins.

Sauropod expert Philip Mannion told me, “Although this isn’t a well-preserved specimen, it is really interesting for building the larger picture of dinosaur evolution.”

“It is the first known diplodocid from South America, perhaps more closely related to African than North American and European diplodocids, and the first known diplodocid that survived into the Cretaceous.”

In future, it is possible that this dinosaur will tell us quite a bit about how sauropods dispersed and migrated. It is particularly important because it was the same time as when the supercontinent Pangaea was undergoing fragmentation into the continents we recognise today. It also sheds light on the geographical nature of extinctions at a time when many animals may have been undergoing large-scale transitions.

The pace at which we find new fossils has gone up significantly, so much that a new dinosaur species is named less than every two weeks. We now have so many fossils that new ones just aren’t as important as they used to be individually. What is important is how they add to our reconstruction of the bigger evolutionary stories. By unravelling the history of co-evolution between Earth and its animals, we may be able to learn much about our future, too.

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