World’s oldest snake discovered
SNAKES ARE MORE THAN 70 million years older than previously thought, according to a researcher who chanced upon the oldest-known snake fossil in a museum collection.
The discovery started with a shot of good luck, says Dr Michael Caldwell, Curator of Lower Vertebrates from the University of Alberta in Canada. He was studying ancient lizards from the massive collections of the Natural History Museum in London, when he stumbled upon the world’s oldest snake.
“I’d decided I should spend some time studying the lizard specimens from the Jurassic and Lower Cretaceous of England that had been described as Parviraptor estesi. The moment I got the left maxilla (jaw bone) under the microscope, I knew it was a snake,” says Michael.
World’s oldest snake a chance discovery
The findings, reported this week in Nature Communications, are based on specimens originally collected more than 150 years ago, which were first thought to belong to an ancient lizard, according to a 1994 analysis. By pure chance, 10 years later Michael decided to take a second look at the specimen and was surprised by what he saw.
“Finding something in the field is like finding pirate treasure never seen before, but finding something in a museum that someone once put a name on, that no one realised is something else…well, wow! You get to rewrite knowledge through reinterpretation,” he says.
The specimen was dated to 140-150 million years ago; another older species found was dated at about 167 mya. Snakes were considered to have originated about 100 million years ago, in the Upper Cretaceous period, but the new analysis pushes that back to the 170 mya, in the Middle Jurassic-Lower Cretaceous.
The evolution of “snakeness”
The researchers studied morphological features of the specimen’s skulls, as well as other fragments available, such as ribs and vertebrae. Their conclusions provide new evidence of the origin and evolution of modern snakes.
“It appears that the head of snakes had evolved the specialisations we associate with ‘snakeness’ today, probably long before their bodies became elongate and limbless,” says Michael.
The findings also suggest these ancient snakes were very diverse and likely lived in many different and unexpected environments, he adds.
After discovering the first specimen (Parviraptor estesi), Michael and his collaborators found three others (Portugalophis lignites, Diablophis gilmorei and Eophis underwoodi) from Portugal, England and Colorado, in a scientific odyssey that took over 10 years, says Michael.
The analyses of more than 3500 species of living snakes as well as fossil snakes was conducted to find and describe all four newly described species.
Edited by Carolyn Barry