Researchers Discover New Species of Ancient Hook-toothed Reptile

With python-like hooked teeth and a body similar to a gecko’s, a newly described Jurassic reptile has links to the origins of lizards and snakes.

A new study detailing the new species, which lived about 167 million years ago and is one of the oldest relatively complete fossil lizards yet discovered, was published this week in the journal Nature by an international team of researchers from the Museum, the United Kingdom, France, and South Africa. 

Nearly 10 years ago, Museum Macaulay Curator Roger Benson and his colleagues, including Stig Walsh from the National Museums Scotland, were on their final part of an expedition on Scotland’s Isle of Skye, where they had been exploring the same limestone platform for multiple days. 

Following a water break and a comment from Benson’s student about how they likely wouldn’t find anything because there were no unexplored spots left, Walsh walked about 15 feet and spotted a fossil—which began a years-long study of what turned out to be the new species, later named Breugnathair elgolensis. This Gaelic name means “false snake of Elgol,” referencing the area where it was found and its unusual characteristics: snake-like jaws with curved teeth and the short body and fully formed limbs of a lizard.

“Snakes are remarkable animals that evolved long, limbless bodies from lizard-like ancestors,” said Benson, the lead author of the study. “Breugnathair has snake-like features of the teeth and jaws, but in other ways, it is surprisingly primitive. This might be telling us that snake ancestors were very different to what we expected, or it could instead be evidence that snake-like predatory habits evolved separately in a primitive, extinct group.”

Lizards and snakes together form a group called squamates, and the researchers placed Breugnathair in a new group of extinct, predatory squamates called Parviraptoridae, which was previously known only from more incomplete fossils.

“I first described parviraptorids some 30 years ago based on more fragmentary material, so it’s a bit like finding the top of the jigsaw box many years after you puzzled out the original picture from a handful of pieces,” said Susan Evans from University College London, who co-led the study. “The mosaic of primitive and specialized features we find in parviraptorids, as demonstrated by this new specimen, is an important reminder that evolutionary paths can be unpredictable.” 

Through computed tomography and high-powered x-ray imaging at the European Synchrotron Radiation Facility in Grenoble, France, the researchers determined how Breugnathair likely appeared in life. Nearly 16 inches long from head to tail, Breugnathair was one of the largest lizards in its ecosystem, where it likely preyed on smaller lizards, early mammals, and other vertebrates, like young dinosaurs. 

Because parviraptorids are thought by some to be the first snakes, the researchers explored whether Breugnathair could be a lizard-like ancestor of snakes. But its unusual mixture of features and the lack of other fossils tied to early squamate evolution prevented them from reaching a conclusive answer. Another possibility is that Breugnathair could be a stem-squamate, a predecessor of all lizards and snakes, that independently evolved snake-like teeth and jaws.

“This fossil gets us quite far, but it doesn’t get us all of the way,” Benson said. “However, it makes us even more excited about the possibility of figuring out where snakes come from.”