240-mn-year-old lizard fossil 'ancestor' of all reptiles

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To better understand both the anatomy of Megachirella wachtleri and the earliest evolution of squamates, the team assembled the largest reptile dataset ever created, using fossils and living specimens from more than 130 lizards and snakes from around the world.

The 240-million-year-old fossil, Megachirella wachtleri, is actually the world's oldest lizard fossil.

To arrive at their conclusions, coauthor of the study Tiago Simoes says that he traveled to more than 50 museums and universities in 17 countries to collect fossil data and study living reptiles to understand their evolution.

"It pushes the origin of lizards back 75 million years".

The fossil was first uncovered in the Dolomites mountain range in Italy, but back when the species was alive, it roamed through the single supercontinent Pangea while the dinosaurs were still recent additions to the prehistoric animal kingdom.

Michael Caldwell is the co-author of the study and a paleontologist at the University of Alberta.

One of the greatest things about the discovery of the Megachirella lizard fossil is that it proves that lizards and snakes survived the mass extinction that killed off the dinosaurs, and also that lizards came into being long before what has been called the Great Dying, as paleontologist Alessandro Palci explained. "With micro-CT, suddenly you can "flip" the fossil over out of its rock".

Megachirella wachtleri walks through plants in this artist's impression of the Italian Dolomites region, about 240 million years ago. The conditions under which the fossil was found - in marine sediments but surrounded by fossilized land plants - suggest that a powerful storm hit the coastline where megachirella lived and swept the tiny critter out to sea.

Simões and his colleagues are still seeking evidence of megachirella's behavior.

Megachirella, which predates the fossils previously thought to belong to the earliest squamates by around 75 million years, bridged the gap between the oldest known squamates and the estimated origins of this reptile group derived from molecular data, researchers reported in a new study. They also used a CT scan that revealed unseen physical characteristics, which included a tiny bone in the lower jaw that is found in other squamates. "In terms of the information that it gives us on the evolution of snakes and lizards".

"It's confirming that we are pretty much clueless", Simões said of the new species.

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