New discovery of Jurassic reptile blurs the line between snake and lizard

A study published in the journal Nature by an international team of researchers, led by the American Museum of Natural History and including National Museums Scotland, describes a previously unknown Jurassic reptile that lived around 167 million years ago. The species has been given the Gaelic name Breugnathair elgolensis, meaning ‘false snake of Elgol’, referencing the area of southern Skye where it was discovered. 

The team came to the ESRF to scan the 167-million-year-old fossil and discovered a mix of morphology traits. Vincent Fernandez, palaeontologist at the ESRF and part of the team, explains the suitability of the ESRF for the sample: “This is a perfect case for the synchrotron: lots of small bones, scattered in small blocks of rock; we had to be able to zoom in on the blocks with good resolution to see minute bones in detail. It can be difficult and sometimes completely impossible to do with a laboratory scanner; whereas with a synchrotron, thanks to the high photon flux, the parallel beam, and the optics instruments, it is quite straightforward”.

A lizard with snake-like jaws

Breugnathair had snake-like jaws and highly recurved teeth, similar to those of modern-day pythons. Unlike living snakes, it had the proportions and limbs of a lizard. The fossil is among the oldest and most complete Jurassic lizards known to science.  

Breugnathair was a squamate, the largest order of scaled reptiles, including lizards and snakes. The species has been placed in a new family, Parviraptoridae, an enigmatic group of extinct, predatory squamates. Previously known from very incomplete remains, parviraptorids were thought by some to be the first snakes. Breugnathair might therefore provide evidence of the lizard-like ancestors of snakes, but it also has primitive anatomical traits suggesting that parviraptorids were stem-squamates, the predecessors of all lizards and snakes. 

Lead author Roger Benson, Curator of Paleontology at the American Museum of Natural History, says: “Snakes are remarkable animals that evolved long, limbless bodies from lizard-like ancestors. Breugnathair has snake-like feature of the teeth and jaws, but in other ways is surprisingly primitive. This might be telling us that snake ancestors were very different to what we expected, or it could instead be evidence for evolution of predatory habits in a primitive, extinct group.” 

The fossil was discovered near Elgol by National Museums Scotland curator Stig Walsh, and is now part of the Museum’s collection. Walsh, co-author of the study, says: “The Isle of Skye is one of the most important Middle Jurassic sites in the world. Breugnathair elgolensis is a remarkable addition to the fossil record, helping to rewrite our understanding of the evolution of snakes and lizards.” 

Professor Susan Evans of University College London, who co-led the study, adds: "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. 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. The mosaic of primitive and specialised features we find in parviraptorids, as demonstrated by this new specimen, is an important reminder that evolutionary paths can be unpredictable." 
 

Reference:

Benson, R.B.J., et al. Mosaic anatomy in an early fossil squamate. Nature (2025). https://doi.org/10.1038/s41586-025-09566-y

Top image: Breugnathair elgolensis artist reconstruction. Image © Brennan Stokkermanslow