The fossil found in the drawer has been found to be the oldest known modern lizard | fossils

The fossilized remains of a small, sharp-toothed lizard, left in a closet for more than half a century, have pushed the origins of the group that includes modern snakes and lizards back tens of millions of years.

The specimen was collected in the 1950s from a quarry near Tortworth in Gloucestershire by the late fossil hunter Pamela L Robinson. But its true identity was not appreciated, as the creature was mislabeled and stored, until recently when it was found at the Natural History Museum in London.

Now researchers say advances in technology have allowed them to take a second look, revealing that the creature occupies a pivotal position in the reptile family tree.

“It’s partly a story of abandoned fossils [a] drawer, and partially a story [that] without the CT scan, you wouldn’t have been able to do the work we did,” said Professor Michael Benton, a palaeontologist at the University of Bristol and co-author of the research.

The long-tailed creature, about 25 cm long, is believed to have lived about 202 million years ago. Cryptovaranoides microlanius. The first term it means a hidden lizard-like animal, referring to its time spent unrecognized and its likely concealment in rock crevices during its lifetime. The second term, which translates as micro-butcher, is a nod to the creature’s curved, blade-like teeth.

Using computed tomography, Benton and his colleagues were able to look at the fossil in great detail and study the bones trapped in the rock. Benson said the animal’s skull was 3 cm long. “The fossil is small, the ribs are only minute,” he said.

The results reveal that the animal was a squamate, one of a group of scaled reptiles that includes creatures such as lizards and snakes. “They start out as lizards — snakes evolve later in the Cretaceous,” Benton said.

The creature has the hallmarks of modern lizards, such as modified bones at the back of the skull to allow extra flexibility in jaw opening, making it the oldest reptile yet found.

“It’s an anguimorph lizard, which today includes 350 species, from the gila monster of North America to the Komodo monitor, the huge predatory lizard of Indonesia,” Benton said.

The team says the find pushes back the origins of modern squamates by at least 34 million years. The oldest known modern lizard was previously thought to have lived about 168 million years ago.

The team adds that the discovery has important implications for understanding the rate of evolution of the tree of life and the time scale and drivers of biodiversity within modern squamates, the latter of which may aid conservation of living species.

“Previously, the common ancestor of all these living forms was dated to the middle Jurassic, but now we’re putting it back to the late Triassic,” Benton said.

He said this while Cryptovaranoides microlanius was the closest scientists now have to the last common ancestor of modern squamates, its advanced features mean the title likely belongs to another, possibly even older, creature.

Professor Steve Brusatte, a palaeontologist at the University of Edinburgh who was not involved in the work, said that while scientists had made many advances in understanding the origins of mammals, birds and crocodiles, the ancestry of lizards and snakes was more of a mystery.

“There are few skeletons of these delicate animals that have been preserved as fossils, and many of them are so fragile that they have proven very difficult to study,” he said.

“If its identification as a modern-style lizard is correct, it meant that lizards were beginning to diversify during the Triassic period, alongside some of the earliest dinosaurs and mammals. It also shows that British fossils are still incredibly important things lurking, either in the field waiting to be discovered or in museum collections waiting to be properly studied.”