A Fossil Found in Museum’s Storeroom Cupboard Has Shifted the Origin of Modern Lizards Back 35 Million Years
An English fossil found in a museum’s storeroom has shifted the origin of modern lizards back 35 million years, according to new research.
The specimen, retrieved from a cupboard at the Natural History Museum in London, has shown that modern lizards originated in the Late Triassic period, and not the Middle Jurassic, as previously thought.
This fossilized relative of today’s lizards—such as monitor lizards and gila monsters—came to the museum’s collection in the 1950s, from a quarry near Tortworth in Gloucestershire. The late Pamela Robinson who recovered the fossils from the quarry did not have access to CT scanning technology to help her gather all the hidden precious details.
As a modern-type lizard, scientists say the new fossil impacts “all estimates” of the origin of lizards and snakes (together called the Squamata), and affects assumptions about their rates of evolution, and even the key trigger for the origin of the group.
The research team have named their amazing discovery Cryptovaranoides microlanius—meaning ‘small butcher’ in tribute to its jaws that were filled with sharp-edged slicing teeth.
Study leader Dr. David Whiteside, of Bristol’ University’s School of Earth Sciences, recalled, “I first spotted the specimen in a cupboard full of Clevosaurus fossils.
“Our specimen was simply labelled ‘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 only survivor of the group, the Rhynchocephalia, that split from the squamates over 240 million years ago.
“We made X-ray scans of the fossils at the University, and this enabled us to reconstruct the fossil in three dimensions, and to see all the tiny bones that were hidden inside the rock.”
The findings, published in the journal Science Advances, shows that Cryptovaranoides is clearly”a squamate as it differs from the Rhynchocephalia in the brain case, in the neck vertebrae, in the shoulder region, in the presence of a median upper tooth in the front of the mouth, the way the teeth are set on a shelf in the jaws, and in the skull architecture—such as the lack of a lower temporal bar.
Dr. Whiteside said there is only one major primitive feature not found in modern squamates, an opening on one side of the end of the upper arm bone, the humerus, where an artery and nerve pass through.
Study co-author Professor Mike Benton explained, “In terms of significance, our fossil shifts the origin and diversification of squamates back from the Middle Jurassic to the Late Triassic.
“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.
“It seems these new plants and animals came on the scene as part of a major rebuilding of life on Earth after the end-Permian mass extinction 252 million years ago, and especially the Carnian Pluvial Episode, 232 million years ago when climates fluctuated between wet and dry and caused great perturbation to life.”
“The name of the new animal, Cryptovaranoides microlanius, reflects the hidden nature of the beast in a drawer, but also in its likely lifestyle—living in cracks in the limestone on small islands that existed around Bristol at the time, where it would have preyed on arthropods and small vertebrates.” said PhD research student Sofia Chambi-Trowell.
“This is a very special fossil and likely to become one of the most important found in the last few decades,” concluded Whiteside.
SLITHER The News to Reptile-Loving Friends on Social Media…