Paleontologists deplume feathery dinosaur.
An international team of researchers that examined the Chinese fossil now concludes that the fibrous structures are not feathers. Even more important for the future, however, the scientists report that the fossil site is awash with specimens--some showing remarkable features seen nowhere else.
"I think this represents a missing chapter in geologic time that has not been recognized until now," says paleontologist John H. Ostrom of Yale University, who led the team. "It is loaded with fossils of birdlike things, dinosaurs, mammal remains, insects, fish, and plants. I suspect that this site will be of major importance 100 years from now," he says.
Accompanying Ostrom were ornithologist Alan H. Brush of the University of Connecticut in Storrs, paleontologist Larry D. Martin of the University of Kansas in Lawrence, paleontologist Peter Wellnhofer of the Bavarian State Museum in Munich, and photographer David Bubier of the Academy of Natural Sciences in Philadelphia, which sponsored the expedition. The scientists described their findings in Philadelphia last week.
The fossil that launched this trip was uncovered last summer by a farmer in Liaoning Province. He split the fossil in two and sold one part to a museum in Beijing and the other to a museum in Nanjing (SN: 10/26/96, p. 260).
During their recent trip to China, Ostrom and his colleagues spent 2 weeks visiting the museums in Beijing and Nanjing and traveling to Liaoning to view the discovery site. After examining the famous fossil with microscopes and hand lenses, the scientists came to an indefinite conclusion. "We do agree: We cannot say. We don't understand exactly what the fibers are," says Ostrom, who has long supported the idea that birds evolved from feathered dinosaurs.
Martin, a steadfast opponent of the bird-dinosaur connection, goes further. "The whole group will agree there are no feathers. The big discussion is whether these fibers are under the skin or above the skin," he says.
If the fibers were within the skin, as Martin believes, they could have been part of a ridge similar to the frill of an iguana. If the fibers sat above the skin, they would be more analogous to feathers or bristles. They could be protofeathers--a structure that preceded the evolution of true feathers, says Brush.
Beijing paleontologists have named their fossil sinosauropteryx. Ostrom and the international team, however, concluded that the Chinese dinosaur may fit into a rare genus called Compsagnathus, known previously from only two fossils in Europe.
While studying another specimen of the same dinosaur, also from the northeast China site, the scientists found the jawbone of a tiny mammal in the gut of the larger beast--the first evidence of a dinosaur preying on our early relatives. The same site has also yielded early bird fossils and possibly the first known flower, says paleontologist Don Wolberg, who organized the academy trip.
The age of the site remains an object of contention. Chinese and Western scientists have reported various dates ranging from 140 to 120 million years ago, a span that stretches from the end of the Jurassic period to the beginning of the Cretaceous. Ostrom and his colleagues collected specimens of volcanic rocks that should allow scientists to determine more exactly the age of the fossils.
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|Title Annotation:||research indicates chicken-size fossil found in China did not have feathers|
|Article Type:||Brief Article|
|Date:||May 3, 1997|
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