BEIJING (XINHUA, NYTIMES) - Chinese scientists have found the remains of a bizarre Jurassic dinosaur with membranous wings, showing a strange attempt to fly in the evolution process from dinosaur to bird.
The well-preserved fossil, discovered in north-east China's Liaoning province, dates back 163 million years and belongs to a new species of Jurassic non-avian theropod dinosaur with associated feathers and membranous tissues.
About 32cm long and weighing about 306g, the new species has been named Ambopteryx longibrachium, meaning a mixture of a dinosaur and the membranous wings of the pterosaur.
The newly discovered dinosaur belongs to the enigmatic clade of the Scansoriopterygidae, one of the most bizarre groups of non-avian theropods, said researcher Wang Min at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences.
When Dr Wang, a vertebrate paleontologist, first saw the fossil, he thought it was a bird.
Birds evolved from dinosaurs, and so the two groups share many features.
Dr Wang assumed that Ambopteryx was a bird because the animal sported relatively long forelimbs, just as modern birds do. But as his team carefully chipped away the rock surrounding the fossil over the course of about a year, distinctly dinosaurian features began to emerge. Ambopteryx, for one thing, had long fingers, a trait that birds lack.
Dr Wang's team was also surprised to find the remains of soft tissue around the dinosaur's arms and torso. This tissue, in life, formed flaps of skin that probably resembled bat-like wings, Dr Wang said.
The new find, published in the academic journal Nature as a cover story, follows a report in Nature in 2015 - by a team including authors of the new paper - that described the only other known bat-like dinosaur. That animal, called yi qi, was the first of its kind, and other paleontologists were sceptical. The doubts arose because yi qi was so bizarre.
"I think that if you had asked a paleontologist to just draw up some kind of fantasy dinosaur... a lot of us never would have come up with something that was that weird," said vertebrate paleontologist Stephen Brusatte at the University of Edinburgh, who was not involved in the new research.
But the discovery of Ambopteryx, which is a close cousin of yi qi, "pretty much seals the deal that there was this group of dinosaurs with bat-like wings", he said.
The latest discovery showed that bat-like dinosaurs definitely existed. But exactly how Ambopteryx flew through the air remains unclear.
The team's best guess is that the animal's flying style was "halfway between a flying squirrel and a bat", said co-author Jingmai O'Connor, a vertebrate paleontologist at the Chinese Academy of Sciences.