Artistic reconstruction of the fossil squamate, Bellairsia gracilis, basking on a dinosaur footprint. Credit: Artwork by Dr. Elsa Panciroli
A fossil discovery from Scotland has actually offered new info on the early development of lizards, during the time of the dinosaurs.
The small skeleton found on the Isle of Skye, called Bellairsia gracilis, is only 6 cm (2.4 inches) long and dates from the Middle Jurassic, 166 million years back. The extraordinary new fossil consists of a near-complete skeleton in life-like articulation, missing out on only the snout and tail. This makes it the most total fossil lizard of this age anywhere in the world.
Bellairsia has a mixture of modern-day and ancestral features in its skeleton, providing proof of what the forefather of todays lizards (which become part of the larger animal group referred to as squamates) might have looked like.
The research, a joint job in between researchers at the universities of Warsaw, Oxford, and UCL (University College London), is reported in the journal Nature. First author Dr. Mateusz Tałanda (University of Warsaw and UCL) said: This little fossil lets us see development in action. In paleontology, you hardly ever have the opportunity to deal with such complete, well-preserved fossils coming from a time about which we know so little.
The actual fossil of Bellairsia gracilis, a fossil squamate from Middle Jurassic aged rocks from the Isle of Skye, Scotland. Fossil kept in the collections at National Museums Scotland. Credit: Photo by Dr. Elsa Panciroli
The fossil was discovered in 2016 by a group led by Oxford University and National Museums Scotland. It is among several new fossil discoveries from the island, including early amphibians and mammals, which are exposing advancement of essential animal groups that continue to the present day.
Dr. Tałanda commented: Bellairsia has some contemporary lizard features, like traits connected to cranial kinesis– thats the motion of the skull bones in relation to one another. This is an essential functional feature of many living squamates.
Co-author Dr. Elsa Panciroli (Oxford University Museum of Natural History and National Museums Scotland) who discovered the fossil, stated: It was one of the very first fossils I discovered when I began dealing with Skye. The little black skull was poking out from the pale limestone, but it was so small I was lucky to identify it. Looking closer I saw the tiny teeth, and recognized I d discovered something essential, but we had no concept until later on that practically the entire skeleton was in there.
The fieldwork site on the Isle of Skye in Scotland, where the fossil was found. Including Prof. Roger Benson (University of Oxford). Credit: Photo by Dr. Elsa Panciroli
Squamates are the living group that consists of snakes and lizards, and makes up more than 10,000 types today, making them among the most species-rich living vertebrate animal groups. They consist of animals as varied as geckos, snakes, and chameleons, found worldwide. The group is defined by numerous specialized functions of the skull and remainder of the skeleton.
We know the earliest origins of squamates lie 240 million years earlier in the Triassic, a lack of fossils from the Triassic and Jurassic has actually made their early evolution and anatomy challenging to trace.
Evaluating the brand-new fossil alongside living and extinct fossil squamates validates Bellairsia comes from the stem of the squamate household tree. This implies that it split from other lizards prior to the origin of modern groups. The research also supports the finding that geckos are an extremely early branching family tree, which the enigmatic fossil Oculudentavis, previously suggested to be a dinosaur, is likewise a stem squamate.
Digital image of the fossil of Bellairsia gracilis inside the rock, as exposed using microCT scan data. Credit: Digital render by Matthew Humpage/NorthernRogue
To study the specimen, the team used X-ray computed tomography (CT) which, like medical CT, enables non-invasive 3D imaging. This permitted the researchers to image the whole fossil, although the majority of the specimen is still hidden by surrounding rock. Whereas medical scanners work at the millimeter scale, the Oxford University CT scanner revealed details to a few tens of micrometers.
Parts of the skeleton were then imaged in even greater information, consisting of the skull, hindlimbs and hips, at the European Synchrotron (ESRF, Grenoble, France). The strength of the synchrotron beam allows a resolution of 4 micrometers, revealing information of the tiniest bones in the skeleton.
Co-author Professor Roger Benson (Department of Earth Sciences, University of Oxford), stated: Fossils like this Bellairsia specimen have substantial value in filling gaps in our understanding of evolution and the history of life in the world. It utilized to be nearly impossible to study such tiny fossils like this, but this research study reveals the power of new strategies consisting of CT scanning to image these non-destructively and in terrific detail.
Co-author Professor Susan Evans (UCL), who initially explained and named Bellairsia from a couple of jaw and skull bones from Oxfordshire 25 years earlier, included: It is fantastic to have a complete specimen of this tantalizing little lizard, and to see where it fits in the evolutionary tree. Through fossils like Bellairsia we are gaining a much better understanding of early lizard anatomy. Angus Bellairs, the lizard embryologist after which Bellairsia was initially named, would have been thrilled.
Reference: “Synchrotron tomography of a stem lizard illuminates early squamate anatomy” by Mateusz Tałanda, Vincent Fernandez, Elsa Panciroli, Susan E. Evans and Roger J. Benson, 26 October 2022, Nature.DOI: 10.1038/ s41586-022-05332-6.
The study was led by Dr. Mateusz Tałanda (University of Warsaw) and involved researchers from the University of Oxfords Earth Sciences Department, Oxford University Museum of Natural History, UCL (University College London), the European Synchrotron Radiation Facility, the Natural History Museum in London and National Museums of Scotland.
Funding was offered by the Ministry of Science and Higher Education, Poland. The John Muir Trust supplied access to the Elgol Coast Site of Special Scientific Interest, and NatureScot given permits for fossil collection.
Author Dr. Mateusz Tałanda (University of Warsaw and UCL) said: This little fossil lets us see development in action. The actual fossil of Bellairsia gracilis, a fossil squamate from Middle Jurassic aged rocks from the Isle of Skye, Scotland. Co-author Dr. Elsa Panciroli (Oxford University Museum of Natural History and National Museums Scotland) who discovered the fossil, said: It was one of the first fossils I discovered when I started working on Skye. Evaluating the brand-new fossil alongside living and extinct fossil squamates verifies Bellairsia belongs to the stem of the squamate family tree. The research likewise supports the finding that geckos are a really early branching family tree, and that the enigmatic fossil Oculudentavis, previously suggested to be a dinosaur, is also a stem squamate.