Pterosaurs Were Super-Social Flying Reptiles
Three Pteranodon Longicepts fly over a misty prehistoric seascape, with two diplodocus dinosaurs near the shore.
A tragedy that claimed the lives of hundreds of pterosaurs 120 million years ago is now providing a slice of prehistoric life, revealing that these dinosaur-era flying reptiles were extremely social creatures.
Discovery of the disaster site, described in the latest issue of the journal Current Biology, includes the first known 3-D pterosaur eggs, thousands of fossilized pterosaur bones, and nearly fully intact pterosaur skulls of both males and females. The remains represent a new pterosaur genus and species: the formidable-looking Hamipterus tianshanensis.
Sediments at the site strongly suggest that a huge colony of these large flying reptiles bit the dust during a violent storm. Beforehand, young and old alike were enjoying life next to what was then a peaceful, scenic lake.
Pterosaurs therefore definitely were not solo, or lonesome. Adults lived around youngsters in crowded surroundings that must have been buzzing with social activity.
"Based on the discoveries, we know that this pterosaur lived together with other pterosaurs and laid its eggs in the bank of the ancient lake, similar (behavior) to that of some modern birds, such as flamingos," lead author Xiaolin Wang told Discovery News.
Wang, a vertebrate paleontologist at the Chinese Academy of Sciences, added that male and female pterosaurs looked very different from each other in terms of size, shape and heftiness, with males of this particular species sporting an elaborate crest that they might have used to woo potential mates.
Wang and his colleagues studied the fossils found at the site, located in the Turpan-Hami Basin, south of the Tian Shan Mountains in Xinjiang, northwestern China.
Back in the prehistoric day, the pterosaurs must have been attracted to the area because of food opportunities and the lakeside's moist environment.
The first three dimensionally preserved pterosaur egg.Maurillo Oliveira
The researchers determined that their eggs consisted of a thin, calcium carbonate shell covering a soft, thick membrane that surrounded the developing pterosaur.
"This makes pterosaur eggs similar to that of the 'soft' eggs of some modern snakes," Wang said, explaining that the eggs therefore had to be laid "in a moist environment, because the eggs needed water from the outside."
The snake similarity makes sense, given that pterosaurs were reptiles and would have been distantly related. Although pterosaurs had wings and could fly, they did not give rise to birds. All pterosaurs went extinct at the end of the Cretaceous, when non-avian dinosaurs and many other animals also died out.
It's even possible that pterosaurs and the earliest birds were archenemies.
Scientists at the University of Chicago and the Field Museum recently found that there was a striking lack of diversity among the earliest known birds.
"There were no swans, no swallows, no herons, nothing like that," lead author Jonathan Mitchell said. "They were pretty much all between a sparrow and a crow."
One feasible explanation is that the literal early birds continuously had to compete with pterosaurs. Another is that birds were simply newer to the scene and hadn't had time yet to diversify. In the long run, however, birds won out, surviving the mass extinction that did in pterosaurs.
The eccentric and social flying reptiles may be long gone, but their lifestyle and looks still make quite an impression. They are, for example, the subject of a huge exhibition featured now through early 2015 at the American Museum of Natural History.
As American Museum of Natural History spokesperson Kendra Snyder told Discovery News, "Pterosaurs were winged reptiles that flew with their fingers, walked on their wings, and ranged from the size of a sparrow to that of an F-16 fighter jet."