The fossil of a mandible that rose to the surface in a limestone region off the coast of the Isle of Skye, Scotland, has led scientists to discover the skeleton of a pterosaur, which proves that these remarkable flying reptiles grew tens of millions of years earlier. than previously thought.
Researchers announced on Tuesday (22) that the pterosaur in question, named Dearc sgiathanaclived about 170 million years ago during the Jurassic period, soaring over lagoons in a subtropical landscape and catching fish and squid with its serrated teeth, perfect for gripping slippery prey.
The scientific name, which is pronounced “djárk ski-an-ach” means “winged reptile” in Gaelic.
With a wingspan of about 2.5 meters, Dearc is the largest known pterosaur from the Jurassic period, and the largest flying creature that had ever existed on the planet up to that time. Some pterosaurs reached even greater dimensions in the subsequent Cretaceous period, when they reached the size of hunting jets. But Dearc shows that this major advance had origins much earlier than imagined.
A forensic analysis of its bones indicates that this particular Dearc specimen was still growing and could have reached a wingspan of ten feet as an adult.
Dearc had a very small weight — possibly less than 10 kilograms — thanks to its light, hollow bones and slender frame, said Natalia Jagielska, a doctoral candidate in paleontology at the University of Edinburgh and lead author of the report published in the scientific journal Current Biology.
The animal had an elongated skull and a long, stiff tail. An arsenal of sharp teeth formed a cage when they closed in on prey.
Pterosaurs, which lived in the company of dinosaurs, were the first of three groups of vertebrates to achieve the ability to fly propelled, 230 million years ago. Birds appeared about 150 million years ago, and bats about 50 million years ago.
Pterosaurs are among the rarest vertebrates in the fossil record, due to the fragility of their bones, which in some cases have walls thinner than a sheet of paper.
“Our specimen is an anomaly in that it is well preserved — retaining its original three dimensions and being nearly complete, and still articulated as it would have been when alive. This state of preservation is exceptionally rare in pterosaurs,” said Jagielska.
Until the time Dearc lived, pterosaurs were generally modest in size, and many of them did not exceed the size of a gull. The prevailing opinion among scientists was that pterosaurs did not reach the size of Dearc until the Cretaceous, some 25 million years later, with the appearance of creatures such as Huanhepterus, Feilongus and Elanodactylus. Quetzalcoatlus, which appeared about 68 million years ago, had a wingspan of about 11 meters, similar to that of an F-16 fighter jet.
“In the Cretaceous, some pterosaurs became huge. They were some of the most superlative animals that ever lived. Dearc didn’t come close to them in terms of size or grandeur, but it appeared 100 million years earlier. Evolution needed time to produce giants.” like these,” said Steve Brusatte, a paleontologist at the University of Edinburgh and co-author of the study.
“One idea is that pterosaurs didn’t grow until after birds evolved, when the two groups were competing against each other for aerial niches. But Dearc tells us that pterosaurs reached the size of today’s largest birds even before the first ones. birds to evolve, which denies that hypothesis,” added Brusatte.
At the time of Dearc, the UK was closer to the Equator, and existed as a series of separate islands. Dearc lived in the company of a number of carnivorous and herbivorous dinosaurs, early mammals and marine reptiles.
Dearc was discovered in 2017. The fossil jutted out of a limestone zone at the tidal perimeter, and was visible at low tide.
“We were flabbergasted,” Brusatte said. “Nothing like it had been found in Scotland so far.”
They fought the tide, using first hammers and chisels and later diamond-tipped saws. But the tide stopped the work before the fossil could be extracted.
“The tide came in strong, and we cried when we saw the waves covering the fossil. We thought we had lost it,” Brusatte said. “But we decided to return to the place at midnight, with lamps and lanterns. We were shocked but happy to find that the bones were still there when the waves receded.”
Translation by Paulo Migliacci.
