A team of Chinese and American scientists has announced in the British science journal Nature the discovery in China of a well preserved 130-million-year-old fossil dinosaur covered from head to tail with primitive feathers.
The researchers have identified the fossil as a "dromaeosaur,” a small, fast-running dinosaur. It was unearthed in an area of fossil beds in northeast China's Liaoning Province. They believe the predator dinosaur is the species closest to the evolution of birds so far discovered.
Pictures of the fossil provided by Ji Qiang, a research fellow at the Chinese Academy of Geological Sciences, clearly shows impressions of feathers from the 80-cm-long dromaeosaur on the surrounding rocks.
The first scientist engaged in the study of the new finding, Ji said that it was an adult dinosaur. It had feather-like structures on the arms and tail, which suggest the primitive organization of feather fibers into adjacent rows of parallel lines, as seen on modern birds.
Ji and his American colleague Mark Norell, chairman of the division of paleontology at the American Museum of Natural History in New York, have formed a team to do research on the dromaeosaur.
They believe the fossil provides key evidence for studies of the evolution of feathers, which turned gradually from fluff to plumes with different functions, such as tail plumes and flight plumes.
This fossil helps make the case that in small, flightless dinosaurs like this one, feathers may have evolved as coverings to keep the body warm, and were only later co-opted for flight, said Ji.
Earlier, other bird-like dinosaurs with primitive feathers, such as Sinosauropteryx and Sinornithosaurus, were found in the same fossil beds in Liaoning. However, the feathers on the dromaeosaur are more evolved than those on the others.
So far, scientists have found some 100 anatomical features common to birds and dinosaurs.
The scientific tracing of the origin of birds started 140 years ago. The link between dinosaurs and birds was first proposed by Thomas Henry Huxley in the mid-1800s.
The fossil of Sinosauropteryx unearthed in Liaoning in 1996 provided the first evidence of the evolutionary relationship between birds and dinosaurs.
Consisting of layers of volcanic and sedimentary rock, the geological formation in Liaoning has yielded an enormous variety of fossilized fish, birds, insects, reptiles shrimps, flowers, mammals and dinosaurs, dating back to the late Jurassic and early Cretaceous periods, 145-120 million years ago.
At that time, the region was dotted with freshwater lakes and volcanoes. Animals that died in or fell into the lakes were entombed on the lake bottoms by volcanic ash, which over millions of years petrified.
China announces new finds in the region every year.
Another two dromaeosaur fossils were discovered at the same site recently.
(Xinhua 04/27/2001)
