A fossil recovered a decade ago from Scotland’s Isle of Skye is offering new insights into one of paleontology’s most enduring mysteries: the evolutionary origins of snakes.
The 167-million-year-old specimen, named Breugnathair elgolensis, which translates to “false snake of Elgol,” represents one of the oldest and relatively complete squamate fossils ever discovered, raising new questions about how snakes evolved from their lizard ancestors.
The fossil belongs to a newly identified family called Parviraptoridae, an enigmatic group that persisted for over 20 million years during the Middle Jurassic to Early Cretaceous periods. What makes Breugnathair extraordinary is its unique combination of anatomical features that doesn’t match any living group, displaying what scientists call “mosaic anatomy.”
“The Jurassic fossil deposits on the Isle of Skye are of world importance for our understanding of the early evolution of many living groups, including lizards, which were beginning their diversification at around this time,” explained University College of London Professor and study co-author Susan Evans.
According to the study, published this week in Nature, this creature exhibited a unique combination of snake-like and lizard-like features. It possessed snake-like dental features, including strongly recurved, conical teeth similar to those of modern pythons, yet retained well-developed limbs and body proportions resembling those of monitor lizards.
This discovery significantly extends our understanding of early snake evolution, which has been hampered by a sparse fossil record. Previous studies have identified snake fossils dating back 140-167 million years, pushing back the origins of snakes by nearly 70 million years from what was previously known. However, most of these early specimens were fragmentary, leaving unanswered important questions about snake anatomy.
“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,” Evans said. “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.”
The evolutionary path to modern snakes appears far more complex than previously thought. During the Middle Jurassic to Early Cretaceous period, snake ancestors underwent significant experimentation with different body plans and feeding strategies. Rather than a linear progression from lizard to snake, the fossil record suggests multiple groups independently evolved snake-like features, particularly specialized teeth for gripping prey.
This latest fossil find appears to tell an interesting evolutionary story. Roughly 16 inches long, Breugnathair was one of the largest lizards in its ecosystem. While it would have fed on smaller lizards, mammals, and other vertebrates, it possessed an unusual mix of features that leaves the researchers unsure how it fits into the ancestry of lizards and snakes. Is this a lizard-like ancestor of snakes? Or is it a curious pivot of Mother Nature? Due to its unusual mixture of features and because other fossils that shed light on early squamate evolution are rare, the researchers did not arrive at 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.
The discovery has significant implications for understanding reptilian evolution during a critical period in Earth’s history. The Middle Jurassic was a period during which squamates underwent significant diversification. Recent research suggests that all major squamate groups achieved their basic ecological adaptations approximately 50 million years earlier than previously thought, during this period.
Moreover, the study highlights the critical need for more high-resolution anatomical data from early squamate fossils to gain a comprehensive understanding of this pivotal period in reptilian evolution. Breugnathair’s mix of characteristics suggests that even older snake fossils await discovery, potentially further extending the timeline of snake evolution.
“This fossil gets us quite far, but it doesn’t get us all of the way,” lead author Roger Benson, Macaulay Curator in the American Museum of Natural History’s Division of Paleontology, said.
“However, it makes us even more excited about the possibility of figuring out where snakes come from.”
MJ Banias covers space, security, and technology with The Debrief. You can email him at mj@thedebrief.org or follow him on Twitter @mjbanias.