Chinese paleontologists have recently found a new "haired" pterosaur fossil in the Inner Mongolia Autonomous Region in North China after the discoveries of famous feathered dinosaurs in its neighboring areas.
"The specimen provides key clues to diversified haired creatures among reptiles in Mesozoic era," said Dr. Wang Xiaolin, researcher with the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences.
"The hair-like integumentary structure could exist in other Mesozoic animals besides dinosaurs and birds, which have descended from dinosaurs," he added.
Scientists found that the pterosaur's "hair" bears some resemblance to that of some feathered dinosaurs, and they have put forward a hypothesis that the two kinds of integument might have come from the same structure of their common ancestors.
However, to prove they are homologous needs much comparison between the two structures, said Wang, also an expert in pterosaurs and dinosaurs.
The nearly intact fossil is in better condition than any of the other recently discovered fossils of its kind with well-preserved wing membranes and hair-like integument structure, he said.
Paleontologists now widely recognize that some dinosaurs had feathers since the first discovery of a feathered dinosaur in 1996, but they are not sure about the relations of the "hairs" of pterosaurs with the feather of dinosaurs, birds and other vertebrates, due to the lack of well-preserved fossils.
"If these integuments in pterosaurs prove to be homologous to the proto feathers of dinosaurs, we have to accept that bird feathers first appeared outside the dinosaur group," Wang said.
Functionally, the "hairs" of pterosaurs could be used for thermoregulation, enhancing flight and muffling sound when seeking prey.
The pterosaur is the first crawler to develop the ability to fly and did so over 70 million years earlier than birds. They lived for 150 million years and share many similar skeletal features with birds, but they are not so closely related to birds as dinosaurs.
The pterosaur fossil had a wingspan of 90 centimeters. It can help solve many controversial questions. One is how wing membranes were attached to the body, and the fossil shows they were attached to the ankles. Whether they were warm-blooded and "haired" is also controversial, and the fossil proves the presence of "hairs", and the possibility of a thermoregulation function.
Pterosaurs are referred to a reptile group called Archosaurs, as are dinosaurs, crocodiles and birds.
The fossil was unearthed from the lacustrine Yixian Formation of Ningcheng County of the Inner Mongolia Autonomous Region, to the west of Liaoning Province, where the unique environment has yielded many fossils with exceptionally well-preserved soft issues due to frequent volcanic eruptions in the Early Cretaceous, including mammals, early birds and feathered dinosaurs.
The study was published in the latest issue of the Chinese Science Bulletin, a core periodical from the Chinese Academy of Sciences.
(Xinhua News Agency January 30, 2002)