242 Millionen Jahre altes Reptil Der älteste Vorfahr von Eidechsen, Schlangen und Tuatara | Der Tuatara Sphenodon punctatus aus Neuseeland ist das alleinige überlebende Mitglied der Rhynchocephalia Order, einst ein vielfältiger Zweig von Lepidosauriern

From the article: A tiny skull found on a beach in Devon has rewritten the early history of lizards, snakes and the tuatara, the last survivor of an ancient reptile lineage found only in New Zealand today. The new species dates back 242 million years, making it the earliest known lepidosaur.

Bristol University scientists made a surprise [discovery](https://www.nature.com/articles/s41586-025-09496-9) when investigating the fossilized remains of what looked like some sort of small ancient lizard. The animal turned out to be a lepidosaur – a member of the reptile group that today includes lizards, snakes and New Zealand’s native tuatara (Sphenodon punctatus), and which has since diversified into more than 12,000 living species.

In trying to identify the unknown specimen, the researchers assumed the first lepidosaurs would look like a rough draft of a lizard – with flexible skull joints, teeth on the roof of the mouth, and an open lower temporal bar. Instead, the Devon fossil had only the last of these traits, lacking both palate teeth and a skull hinge. And its skull housed unusually large, triangular teeth not seen in its closest relatives. Rather than a simple „proto-lizard,“ the specimen showed that the earliest lepidosaurs were already experimenting with different skull shapes and feeding strategies.

“The new animal is unlike anything yet discovered and has made us all think again about the evolution of the lizard, snakes and the tuatara,” said Dan Marke. “We had to give it a name to distinguish it from everything else, and we chose Agriodontosaurus helsbypetrae, quite a mouthful, meaning ‘fierce toothed lizard from the Helsby rock‘ after the Helsby Sandstone Formation in which it was discovered.

“This specimen not only provides important information about the ancestral skull of all lepidosaurs but also builds on the growing knowledge that the tuatara, while often called a ‚living fossil,‘ belongs to a once-diverse order of ancient reptiles with a rich evolutionary history.”

The rhynchocephalian A. helsbypetrae dates back to the Middle Triassic, around 242 million years ago – making it the earliest known lepidosaur, some three to seven million years older than anything we’ve so far identified. Today, the order of Rhynchocephalia has just one living species, the tuatara.