蒙大拿州发现最古老的角恐龙化石
文章来源:未知 文章作者:enread 发布时间:2014-12-11 06:01 字体: [ ]  进入论坛
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Scientists have named the first definite horned dinosaur1 species from the Early Cretaceous in North America, according to a study published December 10, 2014 in the open-access journal PLOS ONE by Andrew Farke from Raymond M. Alf Museum of Paleontology and colleagues. The limited fossil record for neoceratopsian--or horned dinosaurs--from the Early Cretaceous in North America restricts scientists' ability to reconstruct the early evolution of this group. The authors of this study have discovered a dinosaur skull2 in Montana that represents the first horned dinosaur from the North American Early Cretaceous that they can identify to the species level. The authors named the dinosaur Aquilops americanus, which exhibits definitive3 neoceratopsian features and is closely related to similar species in Asia. The skull is comparatively small, measuring 84 mm long, and is distinguished4 by several features, including a strongly hooked rostral bone, or beak-like structure, and an elongated5 and sharply pointed6 cavity over the cheek region. When alive, the authors estimate it was about the size of a crow.
 
This discovery, combined with neoceratopsian fossil records from elsewhere, allows the authors to support a late Early Cretaceous (~113-105 million years ago) intercontinental migratory7 event between Asia and North America, as well as support for a complex set of migratory events for organisms between North America and Asia later in the Cretaceous. However, to better reconstruct the timing8 and mode of these events, additional fieldwork will be necessary.
 
"Aquilops lived nearly 20 million years before the next oldest horned dinosaur named from North America," said Andrew Farke. "Even so, we were surprised that it was more closely related to Asian animals than those from North America."


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1 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。
2 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。
3 definitive YxSxF     
adj.确切的,权威性的;最后的,决定性的
参考例句:
  • This book is the definitive guide to world cuisine.这本书是世界美食的权威指南。
  • No one has come up with a definitive answer as to why this should be so.至于为什么该这样,还没有人给出明确的答复。
4 distinguished wu9z3v     
adj.卓越的,杰出的,著名的
参考例句:
  • Elephants are distinguished from other animals by their long noses.大象以其长长的鼻子显示出与其他动物的不同。
  • A banquet was given in honor of the distinguished guests.宴会是为了向贵宾们致敬而举行的。
5 elongated 6a3aeff7c3bf903f4176b42850937718     
v.延长,加长( elongate的过去式和过去分词 )
参考例句:
  • Modigliani's women have strangely elongated faces. 莫迪里阿尼画中的妇女都长着奇长无比的脸。
  • A piece of rubber can be elongated by streching. 一块橡皮可以拉长。 来自《用法词典》
6 pointed Il8zB4     
adj.尖的,直截了当的
参考例句:
  • He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
  • She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。
7 migratory jwQyB     
n.候鸟,迁移
参考例句:
  • Many migratory birds visit this lake annually.许多候鸟每年到这个湖上作短期逗留。
  • This does not negate the idea of migratory aptitude.这并没有否定迁移能力这一概念。
8 timing rgUzGC     
n.时间安排,时间选择
参考例句:
  • The timing of the meeting is not convenient.会议的时间安排不合适。
  • The timing of our statement is very opportune.我们发表声明选择的时机很恰当。
TAG标签: dinosaur fossil horned
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