早期蜥脚类恐龙完整骨架被发现
文章来源:未知 文章作者:meng 发布时间:2010-10-29 02:45 字体: [ ]  进入论坛
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Scientists have discovered in China the first complete skeleton of a pivotal(关键的,中枢的) ancestor of Earth's largest land animals – the sauropod(蜥脚类动物) dinosaurs1. The new species, tentatively(暂时地) dubbed2 Yizhousaurus sunae, lived on the flood plains around Lufeng in the Yunnan Province of South China about 200 million years ago. The species helps explain how the iconic four-footed, long-necked sauropod dinosaurs evolved. Unlike the 120-foot-long, 100-ton sauropod giants that came later, Yizhousaurus was about 30 feet in length, but it shows all of the hallmarks of later sauropods: the beginning of a long neck, a robust3 skeleton and four-legged posture4. It also comes with an intact fossilized skull5 – which is very rare and crucial for understanding its place in the evolution of sauropods.

"Sauropods have these big bones but their skulls6 are very lightly constructed and also very small," said paleontologist(古生物学者) Sankar Chatterjee of Texas Tech University. Chatterjee presents the discovery on Sunday, Oct. 31 at the annual meeting of the Geological Society of America in Denver.

Yizhousaurus's skull is broad, high and domed7, less than a foot long with a short snout(鼻子,猪嘴) , eye sockets8 on the sides for scanning enemies. It has an unusually wide and U-shaped jaw9, in top view, like that seen in later Camarasaurus, said Chatterjee. Numerous serrated and spoon-shaped teeth of the upper and lower jaws10 would shear11 and slide past each other for cutting plant material during feeding. The sturdy teeth and raised neck let the animal very easily nip small branches from treetops and then chew the plant material.

"Once the plant food was ingested, a gastric12 mill(胃齿臼) in the stomach probably provided further mechanical breakdown13 of the plant," Chatterjee explained. Apparently14 the animal was well adapted to a life of eating plants to support its large body.

Besides its telltale(报警的,泄密的) physical features, Yizhousaurus was also found in revealing company. A half century ago spectacular specimens15 of prosauropod dinosaurs such as Lufengosaurus were discovered at the same location. This makes sense, since most paleontologists are of the opinion that prosauropods gave rise to sauropods, despite the fact that the transition has been very vague, Chatterjee said.

"This is why this new one (Yizhousaurus), may bridge this gap," he said.



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1 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》
2 dubbed dubbed     
v.给…起绰号( dub的过去式和过去分词 );把…称为;配音;复制
参考例句:
  • Mathematics was once dubbed the handmaiden of the sciences. 数学曾一度被视为各门科学的基础。
  • Is the movie dubbed or does it have subtitles? 这部电影是配音的还是打字幕的? 来自《简明英汉词典》
3 robust FXvx7     
adj.强壮的,强健的,粗野的,需要体力的,浓的
参考例句:
  • She is too tall and robust.她个子太高,身体太壮。
  • China wants to keep growth robust to reduce poverty and avoid job losses,AP commented.美联社评论道,中国希望保持经济强势增长,以减少贫困和失业状况。
4 posture q1gzk     
n.姿势,姿态,心态,态度;v.作出某种姿势
参考例句:
  • The government adopted an uncompromising posture on the issue of independence.政府在独立这一问题上采取了毫不妥协的态度。
  • He tore off his coat and assumed a fighting posture.他脱掉上衣,摆出一副打架的架势。
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 skulls d44073bc27628272fdd5bac11adb1ab5     
颅骨( skull的名词复数 ); 脑袋; 脑子; 脑瓜
参考例句:
  • One of the women's skulls found exceeds in capacity that of the average man of today. 现已发现的女性颅骨中,其中有一个的脑容量超过了今天的普通男子。
  • We could make a whole plain white with skulls in the moonlight! 我们便能令月光下的平原变白,遍布白色的骷髅!
7 domed e73af46739c7805de3b32498e0e506c3     
adj. 圆屋顶的, 半球形的, 拱曲的 动词dome的过去式和过去分词形式
参考例句:
  • I gazed up at the domed ceiling arching overhead. 我抬头凝望着上方弧形的穹顶。
  • His forehead domed out in a curve. 他的前额呈弯曲的半球形。
8 sockets ffe33a3f6e35505faba01d17fd07d641     
n.套接字,使应用程序能够读写与收发通讯协定(protocol)与资料的程序( Socket的名词复数 );孔( socket的名词复数 );(电器上的)插口;托座;凹穴
参考例句:
  • All new PCs now have USB sockets. 新的个人计算机现在都有通用串行总线插孔。
  • Make sure the sockets in your house are fingerproof. 确保你房中的插座是防触电的。 来自超越目标英语 第4册
9 jaw 5xgy9     
n.颚,颌,说教,流言蜚语;v.喋喋不休,教训
参考例句:
  • He delivered a right hook to his opponent's jaw.他给了对方下巴一记右钩拳。
  • A strong square jaw is a sign of firm character.强健的方下巴是刚毅性格的标志。
10 jaws cq9zZq     
n.口部;嘴
参考例句:
  • The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
  • The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。
11 shear BzhwZ     
n.修剪,剪下的东西,羊的一岁;vt.剪掉,割,剥夺;vi.修剪,切割,剥夺,穿越
参考例句:
  • Every spring they shear off the sheep's wool and sell it.每年春天他们都要剪下羊毛去卖。
  • In the Hebrides they shear their sheep later than anywhere else.在赫伯里兹,剪羊毛的时间比其他任何地方都要晚。
12 gastric MhnxW     
adj.胃的
参考例句:
  • Miners are a high risk group for certain types of gastric cancer.矿工是极易患某几种胃癌的高风险人群。
  • That was how I got my gastric trouble.我的胃病就是这么得的。
13 breakdown cS0yx     
n.垮,衰竭;损坏,故障,倒塌
参考例句:
  • She suffered a nervous breakdown.她患神经衰弱。
  • The plane had a breakdown in the air,but it was fortunately removed by the ace pilot.飞机在空中发生了故障,但幸运的是被王牌驾驶员排除了。
14 apparently tMmyQ     
adv.显然地;表面上,似乎
参考例句:
  • An apparently blind alley leads suddenly into an open space.山穷水尽,豁然开朗。
  • He was apparently much surprised at the news.他对那个消息显然感到十分惊异。
15 specimens 91fc365099a256001af897127174fcce     
n.样品( specimen的名词复数 );范例;(化验的)抽样;某种类型的人
参考例句:
  • Astronauts have brought back specimens of rock from the moon. 宇航员从月球带回了岩石标本。
  • The traveler brought back some specimens of the rocks from the mountains. 那位旅行者从山上带回了一些岩石标本。 来自《简明英汉词典》
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