Wingless theropod gives more clues birds evolved from dinosaurs
David Perlman, Chronicle Science Editor
Thursday, April 26, 2001
©2001 San Francisco Chronicle

A spectacularly intact fossil of a young dinosaur covered from head to tail with striking evidence of primitive feathers and downy fluff has been discovered in Northeast China, scientists are reporting today.

The remarkable creature's well-preserved body, about the size of a large duck, provides the strongest support yet for the theory that feathers first arose for warmth and insulation, not for flight, says Mark Norell, a long time fossil expert at the American Museum of Natural History in New York.

It also offers further strong evidence that many groups of dinosaurs must have been warm-blooded rather than cold-blooded like reptiles, and that some were, in fact, clearly the ancestors of modern birds, Norell said.

The 135-million-year-old fossil is a member of the dromaeosaur group, a two-legged meat-eater that was actually related to the vicious Velociraptor of Jurassic Park fame, as well as to the largest of the once-dominant tribe, the fearsome Tyrannosaurus Rex. The diminutive predator was only three feet from head to its downy reptilian tail.

It was unearthed by farmers last spring in China's fossil-rich Liaoning province, and details of its structure are being reported today by Norell and by Ji Qiang and his colleagues at the Chinese Academy of Geological Sciences in Beijing.

Dinosaurs emerged more than 250 million years ago and inhabited the Earth until their abrupt extinction some 65 million years ago. Paleontologists have been sharply divided between those who maintain that existing fossils clearly show that dinosaurs were the ancestors of modern birds, and those who insist that birds evolved from unrelated ancient beasts sometimes called archosaurs.

Those who deny the dinosaur-to-bird link are a diminishing but contentious group, and yesterday two of them challenged Norell and Ji's contention that the body of this latest fossil does indeed bear early versions of true feathers.

Storrs Olson, an ornithologist at the Smithsonian Institution's National Museum of Natural History, said in an interview that he examined the fossil in Beijing last June. He and many other experts there were "convinced that there were no feathers on the beast," Olson said.

"There was fuzz on the wings and tail, which is exactly where you should see feathers the best developed, but they just ain't there," he said. "The stuff is simply filaments of some kind, and no one really knows just what the stuff is, but it sure ain't feathers."

Larry Dean Martin, a dinosaur specialist at the University of Kansas, is another strident opponent of the evolutionary link between dinosaurs and birds.

He argues instead that birds and crocodiles share the same obscure ancestry and may have evolved from small tree-dwelling "archosaurs" some 220 million years ago.

"If I had a dollar for every discovery that was supposed to nail down the bird-dinosaur connection, I'd be rich," Martin wrote The Chronicle by e-mail. After examining images of the new fossil, Marin asked: "Can you really see anything that looks like a feather there? I think not!"

Norell said the criticisms were not unexpected. The new-found fossil with its intact body covering "clearly shows the typical herring-bone pattern of feathers in parallel lines branching along the backs of shafts," he said. "And the folks who can't see feathers there are simply refusing to give up their old beliefs."

The two-legged predator, he said, had sharp teeth and bones strikingly similar to modern-day birds. "This fossil radically modifies our vision of these extinct animals. It shows us that advanced theropod dinosaurs may have looked more like weird birds than giant lizards," he said.

Norell's fossil was found in a rock formation with layers of volcanic and sedimentary rock filled with an enormous variety of fossil fish, birds, insects, shrimp and even small mammals.

In a seeming paradox, the feathered but flightless member of the dromaeosaur clan actually lived at least 10 million years later than the first true flying bird, the Archaeopteryx whose fossils date back about 145 million years, Norell said.

But that fact simply underscores the fact that evolution does not proceed step-by-step from one development to another, he said. Rather, the process is more like the growth of a bush, with many clumps and branches of features that emerge at different speeds and in different directions.


A flightless feathered dinosaur

Unearthed as an intact fossil in Northeast China, scientists have detected in this dinosaur the strongest evidence yet that some of the animals were covered with feathers and fluffy down - a sure sign, they say, that they were warm-blooded and most probably the ancestors of modern birds. This bird-like theropod dinosaur was about the size of a large duck - 3 feet long from its head to its reptilian tail. Source: Nature; drawing by Mick Ellison, American Museum of Natural History Chronicle Graphic

E-mail David Perlman at dperlman@sfchronicle.com.

©2001 San Francisco Chronicle Page A - 5

 

 

Wingless theropod gives more clues birds evolved from dinosaurs
The fossil of a small, fast running dinosaur closely related to Velociraptor was unearthed last spring by farmers in northeastern China's Liaoning province. Associated Press photo by Beth A. Keiser

Wingless theropod gives more clues birds evolved from dinosaurs

Dr. Mark Norell, left, with the help of Mick Ellison, unveiled a 135-million-year-old fossil of a young dinosaur at the American Museum of Natural History in New York. Associated Press photo by Beth A. Keiser