Evidence from the fossil of a small dinosaur unearthed in China suggests that the creature may have been capable of flying short distances, using wing membranes similar to those of bats.
The 160-million-year-old pigeon-sized dinosaur has been named "Yi qi" — Mandarin for "strange wing." That's because of what researchers have identified as long, stick-like bones extending from its wrists, which may have supported soft, fleshy membranes.
This is the first time that this kind of bone structure has been seen in a dinosaur fossil, researchers reported in a study published in the journal Nature.
"At first, we just didn't know what the rod-like bones were," said study co-author Corwin Sullivan, a Canadian paleontologist working at China's Institute of Vertebrate Paleontology and Paleoanthropology.
It was only when he was researching scientific literature for a completely different project on flying and gliding vertebrates that he found a note that flying squirrels possess a structure of cartilage in their wrists to help support their flight membrane.
"I immediately thought, wait a minute — that sounds familiar!" he said.
The case for a possible bat-like wing was strengthened by the discovery of membrane remnants attached between the long rod bones and the creature's shorter forelimb figures.
Still, it is difficult to tell how much area the membranes would have covered, said study leader Xing Xu.
And the creature likely wasn't a very accomplished flyer, Xu added — it was, possibly, capable of just short glides or fairly inefficient flapping flights. He said it should be considered "a failed experiment in flight along the line to birds, but we don't know why [it failed]."
The specimen is one of just three members of a dinosaur family known as Scansoriopterygidae — some of the smallest dinosaurs known. Yi qi probably weighed less than a pound, with the skull of the fossil measuring just an inch and a half long, the researchers said.
Many different body configurations arose in early birdlike dinosaurs, but it was only with the development of fully feathered wings that modern birds began to evolve, the researchers explained, because they would have been far more efficient than bat-like wings.
Still, the ancient "bat-dinosaur" adds one more clue to the evolution of flying creatures.
"Yi qi lived in the Jurassic, so it was a pioneer in the evolution of flight on the line to birds," study co-author Zheng Xiaoting said. "It reminds us that the early history of flight was full of innovations, not all of which survived."
