The fossil found in the drawer was found to be the oldest known modern lizard
The fossilized remains of a small, sharp-toothed lizard, left in a cupboard for more than half a century, have set back the origins of the group that includes modern snakes and lizards by 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 LeRobinson. But its true identity was not appreciated as the creature was misclassified and stored, until recently when it was found in 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 reptilian family tree.
In part, it is the story of neglected fossils [a] Drawer and part story [that] “Without a CT scan you wouldn’t be able to do the work we did,” said Professor Michael Benton, a paleontologist at the University of Bristol and co-author of the paper.
The long-tailed creature – about 25 centimeters long – is believed to have lived about 202 million years ago. Microlanius cryptophranoids. Chapter one It means a cryptic, lizard-like animal, a reference to the time it spent unknown and its possible hiding in rock crevices during its lifetime. The second term, which translates to microbutcher, is a reference to the creature’s reversed, blade-like teeth.
Using computed tomography, Benton and his colleagues were able to look at the fossil in fine detail and study the bones trapped within the rock. Benson said the animal’s skull measured 3 cm in length. “The fossil is small,” he said, “and its ribs are only minute.”
The results revealed that the animal was a shrew – one of the group of small-sized reptiles that includes creatures such as lizards and snakes. “They start out as lizards — snakes evolving later in the Cretaceous period,” Benton said.
The creature possessed the main distinguishing features of modern lizards, such as modified bones at the back of the skull to allow additional flexibility in opening the jaw, making it the oldest reptile found to date.
“It’s an angiomorph lizard, which today has 350 species, including everything from the gila monster in North America to the Komodo monitor, the huge predatory lizard in Indonesia,” Benton said.
The team says the discovery postpones the origins of modern grasses by at least 34 million years. The oldest known modern lizard was previously thought to have lived around 168 million years ago.
The team adds that this discovery has important implications for understanding the rate of evolution within the tree of life, the timeline and drivers of biodiversity within modern artiodactyls – which may help preserve living species.
“Previously, the common ancestor of all these living forms dated to the middle Jurassic period, whereas now we’re pushing it back to the late Triassic,” Benton said.
He said that when Microlanius cryptophranoids The closest scientists have now come to the last common ancestor of modern crustaceans, its advanced features mean the title probably belonged to another, perhaps even older, creature.
Professor Steve Brusatte, a paleontologist at the University of Edinburgh who was not involved in this work, said that while scientists had made many advances in understanding the mammalian, bird and crocodile theories, the ancestors of lizards and snakes were 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 difficult to study,” he said.
“If defining it as a modern-style lizard is correct, it would mean that lizards began to diversify during the Triassic period, along with some of the earliest dinosaurs and mammals. It also proves that there are amazingly important British fossils still lurking, either in the field waiting to be discovered, or in museum collections waiting to be properly studied.”
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