A well-preserved fossil of a 150 million-year-old dinosaur recently discovered in southern Germany has prompted scientists to rethink the origins and evolution of feathers.
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Dinosaur model in Germany. (Photo: AFP) |
The nearly complete fossil of a chicken-sized dinosaur named Juravenator was found in a limestone block. However, unlike other members of the two-legged carnivorous group known as coelurosaurs, this creature did not have feathers.
“It is definitely a new dinosaur that has never been known before,” said Ursula Gohlich, a paleontologist at the University of Munich, Germany.
Remains of small dinosaurs from the Late Jurassic period are extremely rare. This new fossil is almost complete, except for a missing tail, and shows soft tissue and skin impressions but lacks any trace of feathers.
“Scientists have believed that all representatives of the coelurosaur group had feathers,” Gohlich noted. “Now we have a charming little dinosaur from this group that lacks feathers. That is truly a problem.”
Feathers are thought to have evolved very early in coelurosaur dinosaurs. All members of this group are presumed to have had feathers. However, Gohlich and Luis Chiappe from the Natural History Museum in Los Angeles, California, believe that the evolution of feathers may be more complex than previously thought.
Feathers could have emerged early on but were later replaced by scales in some creatures when they became unnecessary. “Another possibility is that some representatives of coelurosaurs were not fully covered in feathers but only in certain areas,” Gohlich suggested.
The newly discovered Juravenator is quite small, so it may not have been large enough to grow feathers yet. However, Gohlich believes that regardless of its age, it is very unlikely to have had feathers.
The oldest known bird, Archaeopteryx, was also found in southern Germany. It lived 150 million years ago and had feathers, but it remains unclear whether these feathers were used for flying or for insulation.
M.T.
