News in Science

Pterosaur features defy comparison

A well-preserved pterosaur with soft tissues reveals this flying reptile had hair, claws and wings that were unlike anything seen on today's living animals, suggests a new paper.

Analysis of the remains, which date to around 140 to 130 million years ago, indicate pterosaurs were warm-blooded insect eaters that may have lived in trees and possessed sophisticated flying skills.

"Pterosaurs are unique in their bone construction and our study also shows that some of the soft tissues of these creatures differ from anything known today," says study author Dr Alexander Kellner.

Kellner, a paleontologist at the National Museum in Rio de Janeiro, and colleagues made the determinations after studying the remains of the adult pterosaur Jeholopterus ningchengensis, found in Late Jurassic or Early Cretaceous layers of the Daohugou Bed in China.

Wing tissues show the pterosaur had a nearly one metre wingspan with a complex flying membrane located between the animal's body and each of its large fingers. The membrane consisted of up to three layers containing structural fibres, with fibres in each layer oriented in a different direction, forming a reticular pattern.

"We conclude that this pterosaur might have been able to adjust the wing membrane during flight in order to enhance flight capability," explains Kellner, who says the construction might have also permitted pterosaurs to position the wings as desired when not flying. The fibres also gave strength to the wings, preventing tears.

The study, published in the latest issue of the Proceedings of the Royal Society B, further describes hair-like structures that covered the pterosaur's body, including part of the wing membrane.

Unique features

The hairs, previously theorised to have been feathers or protofeathers, consisted of "comparatively thick filaments, differing in structure from mammalian hair."

"Now, what were they?" asks Kellner. "This is the point: (They were) a completely different structure that is not known in any living organism today."

The researchers additionally found a "horny covering" on the pterosaur's claws, "showing that the claws were much longer in life."

"This corroborates with the hypothesis that these animals were good climbers and could have been living in trees," says Kellner.

Italian paleontologist Dr Fabio Dalla Vecchia, one of the world's leading experts on pterosaurs says, "The presence of up to three layers with differently oriented actinofibrils (in the wing membrane) is the most surprising thing in this study."

"They were not observed in other well-preserved specimens and could mean that not all the pterosaur actinopatagia (wing structures) were built the same way," says Dalla Vecchia.

He also says it's important that the new paper has better defined the pterosaur hair-like structures, and their distribution on the body, since this too wasn't known before.

"This is a remarkably well-preserved specimen, showing the importance of the Chinese deposits to understand different aspects of extinct organisms," says Kellner.

"Hopefully more such specimens will come to light to enable us to understand a little more about how such strange animals, the pterosaurs, were functioning."