200-million-year-old lizard found in storeroom cupboard pushes origin of reptiles by 35 million years

According to the team, the finding has pushed back the origins of modern squamates (scaled reptiles) by at least 35 million years, reported The Guardian. Previously, the oldest known modern lizard was thought to have lived about 168 million years ago.

The findings of the study were published in the journal Science Advances. 

The specimen was a squamate, an anguimorph lizard

Dr. David Whiteside, who led the team, explained their findings. 

"I first spotted the specimen in a cupboard full of Clevosaurus fossils in the storerooms of the Natural History Museum in London where I am a Scientific Associate. This was a common enough fossil reptile, a close relative of the New Zealand Tuatara that is the only survivor of the group, the Rhynchocephalia, that split from the squamates over 240 million years ago," he said in a statement.

"Our specimen was simply labeled 'Clevosaurus and one other reptile.' As we continued to investigate the specimen, we became more and more convinced that it was actually more closely related to modern-day lizards than the Tuatara group."

The team made X-ray scans of the fossils at the University, which helped the, to reconstruct the fossil in three dimensions. "And to see all the tiny bones that were hidden inside the rock," said Whiteside.

The results concluded that the animal was clearly a squamate, an anguimorph lizard that includes 350 species including the Gila monster to the Komodo monitor. Cryptovaranoides shares characteristics with modern lizards such as bone connections in their skull suggesting flexibility.

The most important finding in decades

"In terms of significance, our fossil shifts the origin and diversification of squamates back from the Middle Jurassic to the Late Triassic," said co-author Professor Mike Benton. 

"This was a time of major restructuring of ecosystems on land, with origins of new plant groups, especially modern-type conifers, as well as new kinds of insects, and some of the first of modern groups such as turtles, crocodilians, dinosaurs, and mammals. Adding the oldest modern squamates then completes the picture," he explained.

According to Whiteside, the finding is a very special fossil. "We would like to thank the late Pamela L. Robinson who recovered the fossils from the quarry and did a lot of preparation work on the type specimen and associated bones. It was such a pity she did not have access to CT scanning technology to help her observe all the detail of the specimen," he added.

Study Abstract:

Mammals, birds, and squamates (lizards, snakes, and relatives) are key living vertebrates, and thus understanding their evolution underpins important questions in biodiversity science. Whereas the origins of mammals and birds are relatively well understood, the roots of squamates have been obscure. Here, we report a modern-type lizard from the Late Triassic of England [202 million years (Ma)], comprising a partial skeleton, skull, and mandibles. It displays at least 15 unique squamate traits and further shares unidentatan and anguimorph apomorphies. The discovery fixes the origin of crown Squamata as much older than had been thought, and the revised dating shows substantial diversification of modern-type squamates following the Carnian Pluvial Episode, 232 Ma ago.