绿叶鸟网（www.lvyeniao.cn）原创整理的 > 考研英语作文 A beautilly preserved fossil from southern Germany raises questions about how feathers evolved from dinosaurs to birds, two paleontologists argue in a study published Thursday. The 150 million-year-old fossil is a juvenile carnivorous dinosaur about 2 1/2 feet long that scientists named Juravenator, for the Jura mountains where it was found. It would have looked similar in life to the fleet-footed predators that menaced a young girl on the beach during the opening scene of "The Lost World," the second Jurassic Park movie. The fossil's exceptionally well-preserved bone structure clearly puts it among feathered kin on the dinosaur family tree. Because all of its close relatives are feathered, paleontologists would expect Juravenator to follow suit. But a all patch of skin on the creature's tail shows no sign of feathers. And the skin also doesn't have the follicles that are typical of feathered dinosaurs, said Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County. He and Ursula B. Gohlich of the University of Munich describe the fossil in Thursday's issue of the journal Nature. "It has a typical scaly dinosaurian skin," Chiappe said. The paleontologists beli Juravenator's closest known relative may have been a lly feathered dinosaur from China, Sinosauropterix. There are a number of possible explanations for Juravenator's nakedness. Feathers could have been lost on the evolutionary line leading to Juravenator after arising in an ancestor to both it and its feathered relatives. Or feathers could have evolved than once in dinosaurs, cropping up in sister species at different times and places. It is also possible that this particular fossil of Juravenator, which appears to be a juvenile, only grew feathers as an or lost its feathers for part of the year. But there is another possibility as well, said Mark Norell, curator of paleontology at the American Museum of Natural History: It is entirely possible that Juravenator did have feathers, but they simply failed to fossilize. "Feathers are really just difficult things to preserve," Norell said. To support his hypothesis he pointed out that sral fossils of the oldest known bird, archaeopteryx, lack feathers. Whether or not the new specimen raises interesting questions about how feathers — and thus birds — evolved, most experts do not see it as a challenge to the widely accepted view that modern birds are descended from dinosaurs. 恐龙化石有疑问古生物学家思索羽毛进化过程 从体形庞大的恐龙到身材娇小的鸟类，动物的羽毛是如何进化的？在德国南部发现的一具保存完好的恐龙化石日前引起了古生物学家们对动物羽毛进化过程的思考。 古生物学家聚焦恐龙羽毛 据美联社3月15日报道，这具有1.5亿年历史的化石是一只大约2.5英尺长的幼年食肉恐龙留下来的，因为发现化石的地点位于侏罗山，因此科学家们称它为Juravenator。 这具化石保存有异常完好的骨骼结构，因此可以将其明确地归入到恐龙家族中长有羽毛的一类。由于它所有的近亲都长着羽毛，所以考古学家认为Juravenator也是如此。
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