Some Triassic reptiles glided, others had parachutes

BEIJING, July 18 (Chinese medianet) -- Although the

Archaeopteryx from the Jurassic Period is the worlds first known bird, reptiles

such as pterosaurs and kuehneosaurs were flying as far back as 225 million years

ago, during the Triassic and before large dinosaurs roamed the Earth.

Now scientists saysmaller creatures soared

between trees on strange fly-like wings and parachutes. They glided like today's

flying dragons, small lizards that can extend membranes attached to movable ribs

to glide short distances between trees.

The new study of kuehneosaurs, by scientists from the

University of Bristol, England, shows that smaller reptiles used extraordinary

extensions of their ribs to form large gliding surfaces on the side of the body.

The results are detailed in the July 15 issue of the journal Palaeontology.

Kuehneosaurs, up to two feet (70 centimeters) long,

were first found in the 1950s in an ancient cave system near Bristol. Their

lateral wings were always assumed to be some form of flying adaptation, but

their aerodynamic capability had remained unstudied.

Koen Stein, who did the work while a graduate at

Bristol University, has shown that of the two genera found in Britain,

Kuehneosuchus was a glider (it has elongated wings), while Kuehneosaurus, with

much shorter "wings," was a parachutist. As the two forms are so alike in other

respects, it is possible that they are males and females of the same animal.

"We didn't think kuehneosaurs would have been very

efficient in the air, but all the work up to now had been speculation, so we

decided to build models and test them in the wind tunnel in the Department of

Aerospace Engineering at Bristol," Stein said.

"Surprisingly, we found that Kuehneosuchus was

aerodynamically very stable," Stein said. "Jumping from a five-meter tree, it could easily have crossed nine meters distance

before landing on the ground. The other form, Kuehneosaurus, was more of a

parachutist than a glider."

To work out how these creatures controlled their

flight, the researchers had to model different skin flaps over the wing area.

"We also built webbed hands and feet and had an extra

skin membrane between the legs on the models, but these made the flight of the

animals unstable, suggesting that they probably did not have such features,"

Stein said.

(Agencies)