A new species of early reptile from the Triassic period has been discovered, with unique structures growing from its skin that formed an alternative to feathers. This ‘wonder‘ fossil changes our understanding of reptile evolution. The team of scientists, led by the State Museum of Natural History Stuttgart, published the description of the new species in the journal Nature. The skull of the reptile was scanned at the new beamline BM18.
The 247-million-year-old reptile is called Mirasaura grauvogeli, which means ‘Grauvogel’s Wonder Reptile’, in honour of the fossil collector who found it, Louis Grauvogel. The fossil was found in the 1930s in Alsace (France) and transferred to the State Museum of Natural History in Stuttgart in 2019. The bizarre creature shows characteristics from reptiles but presents a dorsal crest with previously unknown, structurally complex appendages growing from its skin, with some similarities to feathers.
The crest was probably used for display to other members of the same species. The finding shows that complex skin structures are not only found in birds and their closest relatives but may predate modern reptiles. This discovery changes our understanding of reptile evolution. “At first scientists were puzzled about the crest, but after preparation, a reptile skull was revealed. We can now safely say that is a new species from a very strange group reptiles called drepanosaurs”, explains palaeontologist Stephan Spiekman, first author of the study, from the State Museum of Natural History Stuttgart, Germany.
In order to analyse the specimen, which was a few centimetres in length and less than 0.5 millimetres in width, the team came to the ESRF’s new experimental station BM18. There, they scanned the skull using X-ray tomography, which revealed a bird-like shape with a narrow, mostly toothless snout, large forward-facing eye sockets and a large, domed skull. Kathleen Dollman, scientist at the ESRF and co-author of the publication, says: “The fossil is incredible and showed these feather-like structures beautifully. I knew that imaging such fine details was going to be challenging, but when we started to see the first images on BM18 I knew that we had found something special”.
Spiekman adds: “Without the ESRF we could not have been able to do the reconstruction of the skull, because the fossil is so small that it is incredibly difficult to scan – it took me four months of working on the data to get the full reconstruction!”. This is the first Nature publication stemming from research carried out at the new BM18 beamline.
With the findings, the team hypothesized that the snout was probably used to extract insects from narrow tree holes, the big forward-facing eyes are typical of animal living in trees and the domed skull shows a fontanelle, which indicates that the specimen was very young when it died. It also had teeth in the roof of the mouth, as many different groups of extinct reptiles do.
Not hairs, not feathers, but something similar
Body coverings such as hair and feathers have played a central role in evolution. They enabled warm- bloodedness by insulating the body, and were used for courtship, display, deterrence of enemies and, in the case of feathers, flight. Their structure in mammals and birds is characterised by longer and more complex skin outgrowths that differ significantly from the simple and flat scales of reptiles.
The crest of Mirasaura consists of individual, densely overlapping appendages that each possess a feather-like contour with a narrow central ridge. While real feathers consist of many delicate branched structures called barbs, there is no evidence of such branching in the appendages of Mirasaura. Because of this, the team believes that the structure of the complex, unique skin appendages of Mirasaura evolved largely independently of those of birds.
Read more on ESRF website