RIO DE JANEIRO, Aug. 5, 2009 (Reuters) — A fossil found in China of a pterosaur, the earliest known flying vertebrate, shows the creatures had unique and complex wing fibers that enabled them to fly with the precision and control of birds, researchers said on Wednesday.

[Photo] A model of a pterosaurs called the Jeholopterus ningchengensis is shown during a news conference at Rio's Federal University in Rio de Janeiro August 5, 2009. The model is on display with a 130-million year-old fossil of the Jeholopterus ningchengensis which was discovered in China. REUTERS/Bruno Domingos

The finding by a team of Brazilian, German, Chinese and British researchers backs up the theory that the reptiles that dominated the skies from up to 220 million years ago, also known as pterodactyls, were not just basic gliders.

A new technique that involves shining ultra-violet rays on the well-preserved fossil found in Inner Mongolia brought out a detailed view of the tissue in the pterosaur's wing, researchers said at a news conference on Wednesday in Rio de Janeiro.

They also found hair-like fibers different from any other animal's that covered the creature's body and part of its wings. This could have helped the animals control their body temperature and shows they were warm-blooded, said Alexander Kellner, a paleontologist at Brazil's National Museum in Rio.

"They are different from other furs we find in mammals and they provide us another hint that these animals were able to control their body temperature, they were hot-blooded animals," said Alexander Kellner, a paleontologist at Brazil's National Museum in Rio.

"This is of great importance to understanding how the pterosaur functioned."

The UV analysis of the fossil showed that the creature had several layers of fibers to control its wings, rather than one as previously thought, suggesting it had more stability and control over its flight than flying animals such as bats.

The pterosaurs, which ranged in size from small up to the largest creatures known to have flown, went extinct about 65 million years ago, around the same time as the mass extinction of dinosaurs.