Toothless 'Dragon' Pterosaurs Dominated Ancient Late Cretaceous Skies

Millions of years ago during the Late Cretaceous, pterosaurs soared through the skies. Now, scientists have found that toothless "dragon" pterosaurs from the Azhdarchidae family were the main ones to have dominated the environment.

The Azhdarchidan pterosaurs actually derive their name from the Persian word for dragon. This group included some of the largest known flying animals of all times; in fact, the largest had a wingspan that reached between 10 and 12 meters. While these "dragon" pterosaurs once had a worldwide distribution, they eventually disappeared from our planet about 60 million years ago. Surprisingly, though, these animals, unlike their predecessors, were toothless.

"This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand," said Alexander Averianov, one of the researchers, in a news release.

Yet studying this group of pterosaurs isn't easy. Pterosaur bones are relatively fragile, which means its difficult to find full specimens.

"Azhdarchidae currently represent a real nightmare for paleontologists: most taxa are known from few fragmentary bones, which often do not overlap between named taxa, the few articulated skeletons are poorly preserved, and some of the best available material has remained undescribed for forty years," said Averianov.

Despite the difficulty in studying this group, though, the researchers found a number of localities where these pterosaurs were present. In fact, the scientists were able to deduce that this was a main group that dominated the ecosystem at the time. This means that these animals played an important role in Cretaceous ecosystems. From this study, the researchers found they could mostly be found near large lakes and rivers and were most common in nearshore marine environments.

The findings are published in the journal ZooKeys.