Ancient Toothless 'Dragon' Once Dominated the Skies

Giant toothless pterosaurs once dominated the skies, and new research suggests that these ancient creatures played an important role in the Late Cretaceous ecosystem.

Described in the journal ZooKeys, these flying "dragons" has wingspans stretching 39 feet (12 meters) across and ruled the skies 60 million years ago. They are members are the Azhdarchidae family, and derive their name from the Persian word for dragon - Aždarha.

Interestingly, despite their formidable size, these pterosaurs were missing the impressive chompers characteristic of their predecessors. The new research suggests they replaced their toothed relatives as the dominant species when high levels of carbon dioxide killed off important microscopic marine creatures, leading to a mass extinction about 90 million years ago.

"This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand," lead author of the study Dr. Alexander Averianov, from the Zoological Institute of the Russian Academy of Sciences, said in a press release.

Fossil records show that pterosaurs were likely the first airborne vertebrates and they took to the skies around 220 million years ago, according to Live Science. However, other than that, scientists know very little about these ancient reptiles since their fossil record is largely incomplete.

Pterosaur bones are more fragile than other dinosaur bones and there are few that have survived general wear and tear. Most Azhdarchidae pterosaur fossils are preserved in soft sediment deposits called Konservat-Lagerstätten. These kinds of fossils are rare for the Late Cretaceous period, so paleontologists have a difficult time piecing together the pterosaur lineage.

"Azhdarchidae currently represent a real nightmare for paleontologists," Averianov commented in the press release.

In a 2008 review of Azhdarchidae, scientists examined 32 bones, but Averianov examined 54 known Azhdarchidae fossils: 51 bones and three fossilized tracks. After close analysis, the researchers found that these flying giants likely inhabited a large variety of environments, concentrated mostly near large lakes and rivers and most common in nearshore marine environments.

According to Live Science, scientists created an online database of fossils called PteroTerra, which maps out the distribution of these ancient creatures using Google Earth, in order to learn more about the evolution of the pterosaur species.