European paleontologists uncovered a near-complete fossil of an early reptile from 240 million years ago during the mid-Jurassic period on the Isle of Skye in Scotland. They believe that the skeleton may help them understand "anatomical transformations" that are crucial to the evolution of reptiles alive today.
The tiny fossil was called Bellairsia gracilis, which is only 6 cm long and comprises a near-complete skeleton in life-like articulation. The only missing parts are the snout and tail, making it the most complete fossil lizard ever found. The findings are published in the study, titled "Synchrotron Tomography of a Stem Lizard Elucidates Early Squamate Anatomy," in the journal Nature.
Ancestor to Over 10,000 Living Species Today
The Bellairsia gracilis was also known as a squamate that lived 240 million years ago and is the ancestor of more than 10,000 living species today.
Mateusz Tałanda, the corresponding author of the study from the University of Warsaw, told Newsweek that discovering the skeleton was preceded by a huge curiosity about the past.
Until now, scientists knew very little about the ancestors of modern groups of reptiles as they were compared to Mesozoic lizards. But Bellairsia is changing the perspective of scientists that will help them recognize extinct groups of lizards unknown to man.
Dr. Tałanda noted that Bellairsia has some features of modern lizards, such as traits related to the movement of the skull bones in relation to another called the cranial kinesis. It is an important functional feature present in living squamates.
Co-author Dr. Elsa Panciroli said that the skeleton was one of the fossils she found when working on Skye. Although it was so small, its little black skull was poking from the limestone, and that is when she spotted it. They had no idea at first what it was until they did an analysis.
Squamates are living groups of species, including lizards, snakes, and chameleons. It is characterized by numerous specialized features of the skull and the rest of the skeleton. Analyzing the new fossil and squadmates confirms Bellairsia belongs to the 'stem' of the squamate family tree and proves that they split from other lizards before the origin of modern groups.
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Using Non-Invasive Imaging to Study the Fossil
The team used X-ray computed tomography (CT), which works like the medical CT to conduct a non-invasive 3D imaging on the entire fossil even though it is mostly hidden in a rock, per the press release via EurekAlert! The Oxford University CT scanner reveals details down to the fine micrometers compared to medical scanners that are only about millimeter scale.
The power of the synchrotron beam allowed them to see in great detail at a resolution of 4 micrometers the fossil's skull, hindlimbs, and pelvis and reveal even the smallest bone of the skeleton.
Professor Roger Benson, a co-author of the study, said that fossils like the Bellairsia specimen fill the gap in understanding the evolution of life on Earth. The study shows the advantages of using high-technologies, such as the CT scan, to image fossils without destroying them. Through the Bellairsia fossil, scientists now have a better understanding of early lizard anatomy.
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