爱珍多龙化石研究新发现-凯发k8官网

爱珍多龙化石研究新发现
文章来源:未知 文章作者:meng 发布时间:2010-05-19 02:26 字体: [ ] 
(单词翻译:双击或拖选)

azendohsaurus(爱珍多龙) just shed its 1 2(归属,联盟) . a careful new analysis of a. madagaskarensis—this time based on the entire 3 rather than on just teeth and 5aligns(排列) this 230-million-year-old animal with a different and very early branch on the 6(爬行动物) 7 tree. many aspects of azendohsaurus are far more 8(原始的) than 9 assumed, which in turn means that its plant-eating adaptations, similar to those found some early 10, were developed independently. the new analysis is published in the journal palaeontology(古生物学) . "even though this extraordinary ancient reptile looks similar to some plant-eating dinosaurs in some features of the skull and dentition(齿系) , it is in fact only distantly related to dinosaurs," says john j. flynn, curator(馆长,管理者) in the division of paleontology at the american museum of natural history. "with more complete material, we re-assessed features like the down-turned 4 and leaf-shaped teeth found in a. madagaskarensis as 11(收敛的,会聚性的) with some herbivorous(食草的) dinosaurs."

the fossil is a member of archosauromorpha, a group that includes birds and crocodilians(鳄目动物) but not 12, snakes, or turtles. the type 13 of the genus(类,种) azendohsaurus was a fragmentary set of teeth and jaws found in 1972 near (and named for) a village in morocco's 14 mountains. the fossils on which the current research paper is based was discovered in the late 1990s in southwestern madagascar. named a. madagaskarensis, this specimen was uncovered by a team of u.s. and malagasy paleontologists in a "red bed" that includes multiple individuals that probably perished(枯萎,灭亡) together. this species was 15 published as an early dinosaur in science over a decade ago, but the completeness of the more recently 16(发掘出的) and studied fossils has provided the first complete glimpse of what this animal looked like and was related to. a. madagaskarensis was not a dinosaur.

a. madagaskarensis lived during the period of time that dinosaurs, crocodile relatives, mammals, pterosaurs(飞龙目) , turtles, frogs, and lizards were getting their start, and all of the continents were connected as the supercontinent pangaea. a. madagaskarensis was 2 to 4 meters long and weighed between 20 and 50 kilos (about 44 to110 pounds). a. madagaskarensis was an efficient herbivore—"a veritable(真正的,名副其实的) four-legged weed-whacker," according to flynn—with teeth modified for slicing vegetation covering not only its jaws, but also the roof of its mouth. even though early archosaurs were commonly thought to be primarily carnivorous(食肉的) , a. madagaskarensis shows that traits associated with herbivory were much more widespread across archosaur 17(爬行动物) .

"now there are many more cases of herbivorous archosaurs," says andré wyss, professor at the university of california, santa barbara. "we are rethinking the evolution of diet and feeding strategies, as well as the broader evolution of the group."

"this is the way science works," says flynn, commenting on the 18 of the fossils. "as we found and 19 more material, it made us realize that this was a much more primitive animal and the dinosaur-like features were really the product of convergent evolution(趋同进化) ."

wyss adds, "in many ways azendohsaurus ends up being a much more fantastic animal than if it simply represented a 20 early dinosaur."



点击收听单词发音收听单词发音  

1 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 mknya     
n.联系,联合
参考例句:
  • there is no affiliation between our organization and theirs,even though our names are similar.尽管两个组织的名称相似,但我们之间并没有关系。
  • the kidnappers had no affiliation with any militant group.这些绑架者与任何军事组织都没有紧密联系。
3 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。
4 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。
5 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。
6 xbiz7     
n.爬行动物;两栖动物
参考例句:
  • the frog is not a true reptile.青蛙并非真正的爬行动物。
  • so you should not be surprised to see someone keep a reptile as a pet.所以,你不必惊奇有人养了一只爬行动物作为宠物。
7 ctqz7m     
adj.进化的;演化的,演变的;[生]进化论的
参考例句:
  • life has its own evolutionary process.生命有其自身的进化过程。
  • these are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
8 vswz0     
adj.原始的;简单的;n.原(始)人,原始事物
参考例句:
  • it is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
  • his book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。
9 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。
10 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》
11 pzdyf     
adj.会聚的
参考例句:
  • a curved-inwards wall has a convergent effect on wall spray.凹型壁面对碰壁喷雾有聚集作用。
  • if a sequence is not convergent,it is divergent.如果一个序列不收敛,我们称它发散。
12 9e3fa64f20794483b9c33d06297dcbfb     
n.蜥蜴( lizard的名词复数 )
参考例句:
  • nothing lives in pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外,没有别的生物。 来自辞典例句
  • can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗? 来自辞典例句
13 xvtwm     
n.样本,标本
参考例句:
  • you'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • this specimen is richly variegated in colour.这件标本上有很多颜色。
14 vocy5     
n.地图册,图表集
参考例句:
  • he reached down the atlas from the top shelf.他从书架顶层取下地图集。
  • the atlas contains forty maps,including three of great britain.这本地图集有40幅地图,其中包括3幅英国地图。
15 273xz     
adv.最初,开始
参考例句:
  • the ban was initially opposed by the us.这一禁令首先遭到美国的反对。
  • feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。
16 e4d49b43cc52eefcadbac6d2e94bb832     
出土的(考古)
参考例句:
  • many unearthed cultural relics are set forth in the exhibition hall. 展览馆里陈列着许多出土文物。
  • some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。
17 45053265723f59bd84cf4af2b15def8e     
n.爬行动物,爬虫( reptile的名词复数 )
参考例句:
  • snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
  • birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》
18 reinterpretation     
n.重新解释,纠正性说明
参考例句:
  • the ancient "book of songs" needs a reinterpretation for the young people.对青年人来说,古代的《诗经》需要做新的解释。
  • optimists are also skilled at using the psychological defense of "reinterpretation" of events.乐观者长于使用对事件“重新解释”的心理防御。
19 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
参考例句:
  • the doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • the young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
20 mgixr     
adj.一般的,普通的,共有的
参考例句:
  • i usually buy generic clothes instead of name brands.我通常买普通的衣服,不买名牌。
  • the generic woman appears to have an extraordinary faculty for swallowing the individual.一般妇女在婚后似乎有特别突出的抑制个性的能力。
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