Tiny 166-million-year-old skeleton found in Scotland “to reveal the secrets of the lizard’s evolution”

Artist’s impression of a Bellairsia gracilis (Oxford University Museum of Natural History)

A tiny 166-million-year-old fossil lizard found in Scotland could fill gaps in scientists’ understanding of how reptiles evolved.

The 6 cm long skeleton discovered on the Isle of Skye is believed to be the most complete lizard fossil of its age found anywhere in the world.

The fossil, which dates back to the Middle Jurassic, when dinosaurs roamed the Earth, includes the footprint of almost a complete lizard skeleton, missing only the snout and tail.

Known as Bellairsia Gracilis, the lizard belongs to a larger animal group known as the scaly reptiles, which today includes more than 10,000 species such as snakes, chameleons, and geckos.

Scientists claimed that their findings, published in the journal Natureit could help “fill the gaps in our understanding of the evolution and history of life on Earth.”

Dr Mateusz Talanda, of the University of Warsaw and University College London (UCL), who is the first author of the study, said: “This little fossil allows us to see evolution in action.

“In paleontology, you rarely have the opportunity to work with such complete and well-preserved fossils from an era we know so little about.”

The origins of squamates are thought to date back to about 240 million years ago, but the lack of fossils made it difficult to trace their first evolution.

To get a more complete picture of Bellairsia, the researchers used an imaging technique known as CT scan – usually used by medical professionals to get internal body images – to reconstruct her skeleton.

Analysis suggests that Bellairsia belongs to what researchers describe as the “stem” of the squamate family tree and separated from other lizards just prior to the origin of modern groups.

Professor Roger Benson, of the University of Oxford, said: ‘Fossils like this Bellairsia specimen are of tremendous value in filling the gaps in our understanding of evolution and the history of life on Earth. In the past it was nearly impossible to study. fossils as tiny as this, but this study shows the power of new techniques, including CT scanning, to imagine them nondestructively and in great detail. “

The Bellairsia gracilis fossil was discovered on the Isle of Skye (PA)

The Bellairsia gracilis fossil was discovered on the Isle of Skye (PA)

The fossil was found in 2016 by a team led by the University of Oxford and National Museums Scotland. It is part of a collection of new fossils discovered on the Isle of Skye that helped explain the evolution of the first amphibians, mammals and other animal groups that are today.

Dr Elsa Panciroli, who discovered the fossil, said: “The little black skull was sticking out of the pale limestone, but it was so small that I was lucky enough to spot it. Looking closer I saw the tiny teeth and realized I had found something important, but we had no idea until after most of the skeleton was in there. “

Study co-author Professor Susan Evans from UCL, who first described and named Bellairsia from some bones of the jaw and skull from Oxfordshire 25 years ago, added: ‘It’s wonderful to have a complete specimen of this tantalizing lizard and see where it fits into the evolutionary tree.

“Through fossils like Bellairsia we are gaining a better understanding of the anatomy of early lizards.

“Angus Bellairs, the lizard embryologist from whom Bellairsia originally took her name, would have been happy.”

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