A tiny, reptilian fossil has been excavated from layers of ancient sandstone, where it was preserved for over 240 million years – predating the dinosaurs.
The little lizard-like creature pinches the record for the oldest known lepidosaur. Until now, this title was held by Wirtembergia, which lived 3-7 million years later.
Lepidosaurs are a group containing lizards, snakes, and the only living member of the order Rhynchocephalia. The only living member of the order is New Zealand's so-called 'living fossil', the tuatara, which, despite the ravages of time, has maintained a very similar appearance to their Mesozoic ancestors.
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The new fossil has also been classified as Rhynchocephalian, based on close analysis of its near-complete skull and skeleton.
"The new beast has relatively large triangular-shaped teeth and probably used these to pierce and shear the hard cuticles of its insect prey, pretty much as the tuatara does today," says vertebrate paleontologist Michael Benton from the University of Bristol.
It's been named 'Agriodontosaurus helsbypetrae', meaning fierce-toothed lizard of the Helsby Sandstone Formation – the Middle Triassic stone in which it was found on a beach in Devon, UK.
This find presents some of the oldest features of lepidosaurs, some of which – made possible using synchrotron CT scans to probe the finer details of this tiny reptile — are surprising scientists.
"The new fossil shows almost none of what we expected… [it's] unlike anything yet discovered and has made us all think again about the evolution of the lizard, snakes and the tuatara," says paleobiologist Dan Marke, also from the University of Bristol.
Though it did have the open temporal bar (similar to a cheekbone) they predicted, Agriodontosaurus's palate lacked teeth, and its skull had no sign of a hinge, two things scientists expected of the first lepidosaurs. What's more, its teeth were surprisingly large.
"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," Marke says.
This research was published in Nature.