A new study looked at the diversity and distribution of toothless "dragon" pterosaurs from the Azhdarchidae family.
Azhdarchidan pterosaurs were some of the largest-known flying animals of all time, with a wingspan of between 32 and 39 feet, Pensoft Publishers reported. The ancient monsters get their name from the Persian word for dragon, "Aždarha."
"Dragon' pterosaurs had a worldwide distribution once and were the last of their kind to survive on the planet, until some 60 [million years ago]. They dominated the skies during the Late Cretaceus and unlike their predecessors, were characteristically toothless," said he author of the study Alexander Averianov, of the Zoological Institute of the Russian Academy of Sciences.
"This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand," he said.
The pterosaurs' fossil record is generally patchy and is mostly confined to sedimentary deposits known as Konservat-Lagerstätten in which the conditions allowed for their preservation. These Lagerstätten are extremely rare for the Late Cretaceous, when most of the Azhdarchidae evolution took place, making their development extremely hard to study
"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." Averianov said.
Despite these troubles the number of localities of azhdarchidan pterosaurs discovered is impressive and could help researchers gain insight into the role the giant "dragons" played in their ancient ecosystem. The pterosaurs most likely inhabited a large variety of environments, but were most abundant near large lakes and rivers.
The research was published recently in the open access journal ZooKeys.
