'Misty-wing': The Isle of Sky is becoming a key place for unlocking pterosaur evolution.
ADVERTISEMENTA new dinosaur-like species has been uncovered in Scotland, giving palaeontologists a precious insight into animal life in the Middle Jurassic.
Researchers from the UK’s Natural History Museum first noticed a few bones sticking out of a boulder during a field trip to the Isle of Skye in 2006. That fossil has now been revealed as a new species of pterosaur, named ‘Ceoptera evansae’.
These flying reptiles - pterosaur literally translates as ‘wing lizard’, like helicopter means ‘spiral wing’ - existed from the Late Triassic to the same extinction event that killed the dinosaurs around 66 million years ago. But their patchy fossil record during the Middle Jurassic has left us largely in the dark about how they evolved.
“This new species is the first of its particular group to have been found in Scotland, and is only the second flying reptile to be named from the country,” said the NHM’s Professor Paul Barrett, who led the discovery expedition and co-authored the new paper describing the species. “It reveals that these animals were much more widespread than would otherwise be known.”
With an estimated 1.6 metre wingspan, Ceoptera evansae took to the skies above a rich fauna during the Scottish Middle Jurassic around 165 million years ago. Experts already know of an ancient aquatic turtle, dinosaurs, fossil mammals, salamanders and another pterosaur.
‘Dearc sgiathanach’, as it was described in 2022, was the first flying reptile to be named from Scotland, after its remarkably well-preserved remains were found on Skye in 2017. Both Derarc and Ceoptera point to a much richer diversity of pterosaurs during the Jurassic period than has previously been realised.
Why is pterosaur evolution shrouded in mystery?
Long before birds flew, pterosaurs were the earliest vertebrates to have evolved powered flight - on wings made from a membrane of skin and muscle.
Since their bones are so fragile, there aren't many pterosaur fossils at all. They also didn’t spend so much time on the ground near rivers and lakes, where dinosaur fossils typically formed.
“Most of what we know about pterosaurs, especially in the Early and Middle Jurassic, comes from a handful of sites known as Lagerstätten [from the German word for deposits] where fossil preservation is exceptional,” explained Barrett.
“Almost everything we know about pterosaur biology and evolution comes from only eight or nine of these key areas around the world.”
Having compared Ceoptera with other pterosaurs, the palaeontologists believe it belongs to a group known as darwinopterans, which straddle the transition between early pterosaurs and the later pterodactyloids.
Their bony discovery - with its distinctive smaller toe, for example - provides some valuable insights about how, when and where this evolution happened.
“'The new species fits very well within the darwinopterans and helps to extend the geographic range of the group from well-preserved material in China to the UK and Argentina,” Barrett added. “It also reveals that these reptiles originated in the Early Jurassic, which is much earlier than had previously been known.”
The experts now think that the darwinopterans persisted for around 25 million years alongside a rich diversity of other pterosaurs, including Dearc. China and the UK are currently the only places where this rare overlap in the fossil record has been found.
How was Ceoptera evansae excavated?
The 18-year gap between the bones being found on Skye and their description published in the Journal of Vertebrate Paleontology this week, points to the painstaking work of fossil study.
The beach near Elgol on the southwest coast of the island where the fossil was found is a Site of Special Scientific Interest, meaning the team could only collect specimens from rocks that had naturally fallen.
“While crawling over these boulders to examine them for fossils, we noticed a few bones sticking out,” Barrett recalled. The top of this rock was collected and taken back to the NHM in London, where a conservator spent over a year exposing the bones through acid preparation and other techniques.
Lead author Dr Liz Martin-Silverstone, a palaeobiologist from the University of Bristol, described the excitement of finding more bones embedded in the rock than they could initially see.
ADVERTISEMENT“It brings us one step closer to understanding where and when the more advanced pterosaurs evolved,” she told the NHM.
There were enough bones to recognise this once free-ranging creature as belonging to a new species.
Ceoptera was so named for the Scottish Gaelic word for mist, 'ceò', as the Isle of Skye is known as the Isle of Mist.
Its specific name of ‘evansae’, appearing after the genus, honours Professor Susan Evans of University College London, who introduced the team to the area of Skye where Ceoptera evansae was spotted. And so 'misty-wing' has entered the list of species.
