2007年VOA标准英语-Scientists Find Conclusive Evidence Velocirapto(在线收听

By Jessica Berman
Washington
20 September 2007

Scientists say they have evidence that a ferocious dinosaur made famous by the movie Jurassic Park definitely had feathers.  Experts say the dinosaur, called Velociraptor, had a wing structure just like modern birds.  VOA's Jessica Berman reports.

A new study by American researcher Alan Turner and his colleagues provides the first conclusive evidence that Velociraptor, a sprinting, vicious dinosaur that lived some 80 million years ago, had feathers.
 
The Velociraptor in the current study is estimated to have been one meter tall, 1.5 meters long and weighed just over 13 kilograms.

Turner, a graduate student at the American Museum of Natural History in New York and lead author of the study, says Velociraptor appears to have been a smaller creature than in Jurassic Park, but just as nasty. 

"It's sort of as if you scaled up a chicken and then gave it really nasty teeth and big claws on its feet," he said.

Fossils of Velociraptor found over the years in Liaoning province in northern China reveal bird-like characteristics, but there haven't been any feathers on the bones unearthed there.

One day, while examining the forearm, or ulna, of a Velociraptor dug up in Mongolia in 1998, Turner made an interesting discovery.

"I just happened to feel these couple of bumps along the backside. And it was like, 'Oh, that's very interesting,'" he recalled.  "And then I kind of let it pass. And then I was thinking about it more later on, and that's when I took it to the high powered microscopes and realized it has all these other features that you would expect to see if it was a quill knob."

The quill knobs found on Velociraptor are regularly spaced bumps along the ulna where flight or wing feathers would have been attached.

"And when you compare them to the ulna of a bird, you see that they correspond quite closely to these quill knobs," he added.  "These wouldn't have been flight feathers in the Velociraptor, because it's an animal that's much too big to have flown.  But it still shows that feathers were attached to the bone there."

Turner thinks Velociraptor might have used the feathers for show, to shield nests or to keep itself warm.

He says his team did not find quill knobs on other fossils of the bird-like carnivore, but that doesn't mean, he said, that Velociraptor did not have feathers. 

The discovery of Velociraptor quill knobs is reported in the journal Science.

  原文地址:http://www.tingroom.com/voastandard/2007/9/43754.html