Washington, May 19 (ANI): A new analysis of a fossil unearthed in China in the 1970s has suggested that the family trees for crocodiles, birds and dinosaurs diverged earlier than originally thought.
The only known specimen of Xilousuchus sapingensis has been reexamined and is now classified as an archosaur. Archosaurs, characterized by skulls with long, narrow snouts and teeth set in sockets, include dinosaurs as well as crocodiles and birds.
The new examination dates the X. sapingensis specimen to the early Triassic period, 247 million to 252 million years ago, said Sterling Nesbitt, a UW postdoctoral researcher in biology.
That means the creature lived just a short geological time after the largest mass extinction in Earth's history, 252 million years ago at the end of the Permian period, when as much as 95 percent of marine life and 70 percent of land creatures perished.
The family trees of birds and crocodiles meet somewhere in the early Triassic and archosauriforms are the closest cousin to those archosaurs, Nesbitt said.
But the new research places X. sapingensis firmly within the archosaur family tree, providing evidence that the early members of the crocodile and bird family trees evolved earlier than previously thought.
The study was published recently in Earth and Environmental Science Transactions of the Royal Society of Edinburgh. (ANI)
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