You don't need feathers to fly: just look at bats and planes . . . and now, dinosaurs.
Chinese scientists have discovered a new variety of dinosaur that had wings made of a skin membrane rather than feathers.
The creature was only slightly larger than a pigeon, and while palaeontologists don't know for certain it could fly, its bizarre wing formation raises questions about how flight may have evolved.
The creature, named Yi qi, which means "strange wing" in Mandarin, was unearthed in rocks from the Jurassic period, about 160 million years ago, in north-east China.
Lead researcher Xing Xu, from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, said the name seemed appropriate given no other bird or dinosaur had a wing of the same kind.
"We don't know if Yi qi was flapping, or gliding, or both, but it definitely evolved a wing that is unique in the context of the transition from dinosaurs to birds," Professor Xu.
While Yi qi belonged to a group of dinosaurs that were closely related to primitive birds, there was no evidence they could fly themselves until the group published their findings in the journal Nature this week.
As well as finding evidence Yi qi had membrane wings, it also possessed a long, slender bone, or cartilage, on each wrist, which researchers inferred was used to support the wing, like in bats and flying squirrels.
Since the 1990s, scientists had been discovering dinosaurs with feathers or feather-like structures, mostly in China, said American palaeontologist Kevin Padian, who was not involved in the research.
"They cemented the hypothesis of the dinosaurian origin of birds and provided spectacular evidence about the origin of flight and the primordial functions of feathers," Professor Padian wrote in a commentary piece for Nature.
While the dinosaur did have feathers, their narrow and thread-like structure was not suitable for flight.
If Yi qi did fly – and there's not enough evidence to confirm it did – it suggests the origin of flight in dinosaurs didn't rely exclusively on feathers.
Flinders University palaeontologist John Long, who was not part of the research, said: "The amazing thing about Yi qi, the totally bizarre new flying squirrel-like dinosaur with bat-like wings and feathers, is that it shows how much evolutionary experimentation went on in dinosaurs before they settled on the right formula for flight, and then evolved into birds."
