A new study suggests that the massive pterosaurs, which ruled the world's skies 60 million years ago, may hold an important clue in understanding changing ecosystems during the age of dinosaurs. Why? Because this particular type of dominant pterosaur didn't have any teeth.
Named after the Persian word for dragon, "adarha," the Azhdarchidae family of flying pterosaurs signaled an important shift in world ecosystems, according to new research. Azhdarchidae replaced its tooth-filled pterosaur relatives around 90 million years ago during a mass extinction. Research suggests this was due to high levels of carbon dioxide having killed off important microscopic marine creatures.
"This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand," Alexander Averianov, from the Russian Academy of Sciences, writes in a new study on the toothless pterosaurs.
Piecing together the pterosaur puzzle is a challenge, even more-so than dealing with the fossils of other prehistoric creatures. Due to the fragile nature of pterosaur bones, fossils often times don't survive and leave an incomplete fossil record for scientists to build their cases on.
Because of this, most Azhdarchidae species are defined only based on a few bones, with more complete skeletons being rare and not well preserved. According to Averianov, this lack of evidence causes researchers to believe they have found new pterosaur species, when in reality they are more likely incorrectly identifying some pterosaur bone fragments.
To better help understand the fully history of the creatures, scientists have created what they are calling PteroTerra. Using Google Earth, PteroTerra is an online database that maps out the distribution of Pterosaur fossils around the world.
Averianov examined 54 known Azhdarchidae fossils in 2008, after which he concluded that most of the pterosaurs probably lived near bodies of water, whether they be lakes, rivers or along coastlines.
Pterosaurs as a whole were likely the first airborne vertebrates judging from fossil records, taking to the skies around 220 million years ago. Though pterosaur fossils are rare, a massive excavation of close to 50 pterosaur fossils discovered in the Brazilian desert may help shed light on how the creatures lived, developed and migrated. Because so many of the creatures were found together in one spot, scientists believe at least some types of pterosaur may have lived in colonies.
Why the creatures were in the desert, when most pterosaur fossils are discovered near water, is still unknown, but may indicate a spring or oasis once existed in the area.
