Chang W. Lee/The New York Times

A diorama of the Tropeognathus, a pterosaur species, at the American Museum of Natural History.

April 10, 2022

First of its Kind Dearc sgiathanach Fossil Discovered in Scotland

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In February, The Current Biology Journal published the discovery of a 170 million-year-old Dearc sgiathanach fossil. Prof. Jeremy Searle, ecology and evolutionary biology, says this discovery further advances the evolutionary department’s understanding of pterosaurs at Cornell.

Amelia Penny, a Ph.D. student at the University of Edinburgh, first discovered the fossil of this large pterosaur on the Isle of Skye, Scotland in 2017. This event marked a revolutionary moment in the field of paleontology. 

Though not a fossil of a full-grown pterosaur, the unearthed Dearc sgiathanach fossil was exceptionally well-preserved and was nearly complete. Well-preserved pterosaur fossils are typically limited to certain rock formations in select parts of the world, making this a rare find in Scotland.

Since most of the pterosaur’s bones had been persevered with minimal damage, paleontologists were able to examine the 3D structure of Dearc sgiathanach bones. This allowed them to closely examine the size, features and age of the pterosaur before its fossilization. 

Searle noted the value of finding a pterosaur fossil this well-preserved and intact. 

“Pterosaurs, like birds, have rather lightweight bones that break easily and don’t fossilize well. So, there are rather few pterosaur fossils this good,” Searle said. 

With an expected wingspan of over 2.5 to 3 meters when full-grown, Dearc sgiathanach was about the size of a vulture. This pterosaur was larger than others found in the Jurassic period which had wingspans limited to less than two meters.

The large size of Dearc sgiathanach suggests that it likely occupied a different niche than smaller pterosaurs of its time. 

“Being larger often means that you can eat larger things. In the case of pterosaurs, they would have taken fish and other marine creatures from the shallow tropical lagoons where they hunted. Dearc sgiathanach would have been able to take larger fish than smaller pterosaurs,” Searle said. 

These findings may provide insight into the occupied niches of pterosaurs, changing the way paleontologists understand pterosaurs today.

“Any explanation of large size in pterosaurs cannot be restricted to understanding the large pterosaurs found in the Cretaceous,” Searle said. “We now know there were some pretty large pterosaurs much earlier than that.”