美国发现新种恐龙化石 可能为三角龙祖先
文章来源:未知 文章作者:enread 发布时间:2011-02-01 01:33 字体: [ ]  进入论坛
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New Haven1, Conn.—Triceratops(三角恐龙) and Torosaurus(牛角龙) have long been considered the kings of the horned dinosaurs2. But a new discovery traces the giants' family tree further back in time, when a newly discovered species appears to have reigned4(统治) long before its more well-known descendants, making it the earliest known member of its family. The new species, called Titanoceratops after the Greek myth of the Titans, rivaled Triceratops in size, with an estimated weight of nearly 15,000 pounds and a massive eight-foot-long skull5.

Titanoceratops, which lived in the American southwest during the late Cretaceous period around 74 million years ago, is the earliest known triceratopsin, suggesting the group evolved its large size more than five million years earlier than previously6 thought, according to Nicholas Longrich, the paleontologist(古生物学者) at Yale University who made the discovery. The finding, which will appear in an upcoming issue of the journal Cretaceous Research, helps shed light on the poorly understood origins of these giant horned dinosaurs.

Longrich was searching through scientific papers when he came across a description of a partial skeleton of a dinosaur3 discovered in New Mexico in 1941. The skeleton went untouched until 1995, when it was finally prepared and identified incorrectly as Pentaceratops, a species common to the area. When the missing part of its frill – the signature feature of the horned dinosaurs – was reconstructed for display in the Oklahoma Museum of Natural History, it was modeled after Pentaceratops.

"When I looked at the skeleton more closely, I realized it was just too different from the other known Pentaceratops to be a member of the species," Longrich said, adding that the specimen's size indicated that it likely weighed about twice as much as adult Pentaceratops. The new species is very similar to Triceratops, but with a thinner frill, longer nose and slightly bigger horns, Longrich said.

Instead, Longrich believes that Titanoceratops is the ancestor of both Triceratops and Torosaurus, and that the latter two split several millions years after Titanoceratops evolved. "This skeleton is exactly what you would expect their ancestor to look like," he said.

Titanoceratops was probably only around for about a million years, according to Longrich, while the triceratopsian family existed for a total of about 10 million years and roamed(漫步,漫游) beyond the American southwest into other parts of the country and as far north as Canada.

In order to confirm the discovery beyond any trace of a doubt, Longrich hopes paleontologists will find other fossil skeletons that include intact(完整的) frills, which would help confirm the differences between Titanoceratops and Pentaceratops.

"There have got to be more of them out there," Longrich said.



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1 haven 8dhzp     
n.安全的地方,避难所,庇护所
参考例句:
  • It's a real haven at the end of a busy working day.忙碌了一整天后,这真是一个安乐窝。
  • The school library is a little haven of peace and quiet.学校的图书馆是一个和平且安静的小避风港。
2 dinosaurs 87f9c39b9e3f358174d58a584c2727b4     
n.恐龙( dinosaur的名词复数 );守旧落伍的人,过时落后的东西
参考例句:
  • The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
  • Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》
3 dinosaur xuSxp     
n.恐龙
参考例句:
  • Are you trying to tell me that David was attacked by a dinosaur?你是想要告诉我大卫被一支恐龙所攻击?
  • He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。
4 reigned d99f19ecce82a94e1b24a320d3629de5     
vi.当政,统治(reign的过去式形式)
参考例句:
  • Silence reigned in the hall. 全场肃静。 来自《现代汉英综合大词典》
  • Night was deep and dead silence reigned everywhere. 夜深人静,一片死寂。 来自《现代汉英综合大词典》
5 skull CETyO     
n.头骨;颅骨
参考例句:
  • The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
  • He fell out of the window and cracked his skull.他从窗子摔了出去,跌裂了颅骨。
6 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
TAG标签: species dinosaurs American
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