Dinosaur fossils rewrite the history of feathers

An intact fossil of a newly discovered 150 million-year-old dinosaur in southern Germany prompted scientists to rethink the birth and development of feathers.

Dinosaur model in Germany.( Photo: AFP )

The complete fossil of a chicken-sized dinosaur named Juravenator is found in a limestone rock. But unlike the other members of the two-legged carnivorous dinosaur group called coelurosaurs , the animal is hairless.

" It is certainly a new dinosaur that has never been known ," said Ursula Gohlich, a paleontologist at the University of Munich, Germany.

Traces of small dinosaurs in the late Jurassic era are also rare. This new fossil is almost complete, in addition to the lost tail, showing soft tissue and skin imprint but no trace of hair.

" Scientists have assumed that all representatives of the coelurosaurs are furry ," Gohlich said. " Now we have a lovely dinosaur belonging to this group but it has no fur. It is really a problem ."

The hair is believed to evolve very early in the coelurosaur dinosaur. All members of this group have feathers. But Gohlich and Luis Chiappe, at the Natural History Museum in Los Angeles, California, believe that the evolution of feathers can be more complicated than people think.

Hair may have been born early but then replaced by scales in some organisms when it becomes unnecessary. "Another possibility is that some representatives of the coelurosaur are not completely covered with fur but only in some areas ," Gohlich said.

The newly discovered Juravenator is still very young, so it may not be big enough to grow hair. But Gohlich said that regardless of age, it is less likely to have feathers.

The oldest known bird, Archeopteryx , was also found in southern Germany. It lived 150 million years ago and has feathers, but it is unclear whether feathers are used to fly or to keep warm.

MT