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

Paleontologists have identified a 240-million-year-old fossil of a lizard as the "ancestor" of all modern lizards and snakes, providing key insight into the origin and evolution of one of the largest groups of vertebrates on Earth.

The fossil -- Megachirella wachtleri -- is known as squamates and was originally found in the early 2000s in the Dolomites Mountains of Northern Italy.

It suggests the origin of squamates is even older, taking place in the late Permian period, more than 250 million years ago.

"The specimen is 75 million years older than what we thought were the oldest fossil lizards in the entire world and provides valuable information for understanding the evolution of both living and extinct squamates," said lead author Tiago Simoes, a doctoral student from the University of Alberta in Canada.

Currently, there are 10,000 species of lizards and snakes around the world, twice as many different species as mammals. Despite this modern diversity, scientists did not know much about the early stages of their evolution.

First discovered more than 15 years ago on Monte Pra della Vacca in the Dolomites mountain range of northern Italy by Michael Wachtler, the researchers considered Megachirella wachtleri as an enigmatic lizard-like reptile but could not reach conclusive placement.

"It is extraordinary when you realise you are answering long-standing questions about the origin of one of the largest groups of vertebrates on Earth," Simoes added, in a paper published in the journal Nature.

To better understand both the anatomy of Megachirella wachtleri and the earliest evolution of lizards and snakes, the team assembled the largest reptile dataset ever created.

The team combined data from both living and extinct reptiles--which involved anatomical data drawn from CT scans and DNA, revealing that the once enigmatic reptile was actually the oldest known squamate.

--IANS

rt/and/vm