The skeleton, discovered in 1910 in a copper mine in central Germany, is of a reptile called Coelurosauravus jaekeli. As well as walking, the animal could glide using a unique set of wings consisting of long, hollow bones that formed directly in flaps of skin, and not as a modification of existing limb structures as is the case in modern-day birds, bats and flying lizards.
It pre-dated the first feathered animal, Archaeopteryx, by almost 100 million years. Instead, the 30-centimetre Coelurosauravus could probably fly for tens of metres by opening out its "wings" like a Japanese fan, and taking off from a suitable high point - rather like modern flying geckos, of which it is an ancestor - and using its long tail for balance in the air.
But scientists have been amazed by the way that the bones grew. "Coelurosauravus is totally bizarre because in every other animal that flies, wing support draws on the normal skeleton," says Hans-Dieter Sues of the Royal Ontario Museum, commenting on the find in today's edition of the journal Science. Bats and birds, for example, have wing bones which are converted forelimbs.
Robert Carroll, a vertebrate paleontologist at the McGill University of Montreal, said: "We typically think of evolution as taking an existing structure and making some new function of it, but this animal has taken the capacity to produce bone and elaborated it in a completely unique way."
The skeleton was discovered by a German copper miner, who labelled it "Flying Reptile". Ironically, the paleontologist he sold it to found the shape so improbably that he reckoned it was two superimposed sets of bones - a fish's fins on top of a reptile.
It is only now that scientists have realised they were wrong. "This demonstrates how early flight, even if not active, flapping flight, was achieved by vertebrates," said Dr Carroll.Reuse content