Fossils shed light on history of ancient pterosaurs

About 147 million years ago, in the skies above Bavaria, ancient flying reptiles pterosaurs with a wingspan of about 2 meters.

Scientists have unearthed the nearly complete skeleton of a reptile named Skiphosoura bavarica . The discovery helps us better understand the evolution of pterosaurs – one of the creatures that played an important role in the ecosystem of the age of dinosaurs.

Reconstructed image of the Jurassic pterosaur Skiphosoura bavarica. (Photo: Gabriel Ugueto).

Skiphosoura lived during the late Jurassic period. Anatomically, it was a bridge between the smaller, long-tailed pterosaurs that lived about 80 million years ago in the Triassic, and the giant, short-tailed pterosaurs that flourished during the Cretaceous—like Quetzalcoatlus, which had a wingspan as wide as an F-16 fighter jet.

"Skiphosoura is of great importance ," said paleontologist David Hone from Queen Mary University of London, lead author of the study published in the journal Current Biology on Monday, because it provides insight into the evolution of flying lizards.

'It also helps us to clarify other pterosaur discoveries we have made, better explain their place in the taxonomy of this group, and allows us to illustrate the transition from early to late forms – as well as identify which features changed and in what order,' said Hone.

The creature, whose scientific name means 'sword tail from Bavaria,' had a short, sword-like tail, which is rare because fossils are usually flattened. The skeleton was unearthed in 2015 in the southeastern German state of Bavaria.

"Pterosaur skeletons are very fragile because their bones are so thin that they often break or crush when preserved ," Hone explains.

Skiphosoura may have been one of the largest flying reptiles in its ecosystem. Its skull was about 25 cm long.

"The bony nose only extends to the front of the snout, but there's a soft tissue extension above it, which makes it look a little larger. We can't be sure yet, but it could be colorful or patterned ," Hone said.

"Its teeth were quite long and sharp, used to puncture and hold prey ," Hone explains. "It probably ate small prey such as lizards, small mammals, large insects and possibly fish. It likely lived in a terrestrial environment, such as in forests."

Pterosaurs, relatives of dinosaurs, were the first group of vertebrates to develop the ability to fly. Birds followed about 150 million years ago, and bats appeared about 50 million years later. They became extinct 66 million years ago when an asteroid collided with Earth.

Paleontologists divide pterosaurs into two main groups. The earliest had short heads, short necks, long tails, short wrists, and long fifth toes on their feet. Later ones had large heads, long necks, short tails, long wrists, and shortened fifth toes on their feet. The later ones also had no teeth.

The discovery of Skiphosoura and another species called Dearc sgiathanach , which lived about 170 million years ago in Scotland, shed light on several important events in the evolution of pterosaurs. The two species belong to a transitional group called darwinopterans , which served as a bridge between primitive pterosaurs and later pterosaurs.

"Skiphosoura sits on the family tree between the darwinopteran pterosaurs and their descendants, the pterodactyloid pterosaurs," said paleontologist and study co-author Adam Fitch from the Field Museum in Chicago.

Over the course of more than 150 million years, pterosaurs shaped a myriad of ecological roles, from aerial predators to ground hunters, roles that birds and their close relatives later inherited.