经济学人165:齿状物所记

 　　Science and technology

　　科学技术

　　Palaeontology

　　古生物学

　　Remember the tooth

　　齿状物所记

　　A link is made in an ancient ecosystem¹

　　古生态系统的一环

　　WHO ate whom in the food chains of the past is rarely clear.

　　过去的食物链中谁吃谁的问题很少能明确下来。尽管哪些物种是捕食者，

　　Though it is obvious which species were predators³ and which prey⁴,

　　而哪些物种又是被掠食者显而易见，

　　the subtle specialisations of feeding habit that allow many types of carnivore to co-exist are rarely preserved in the fossil record.

　　但是让多种类型的肉食性动物共存的摄食习性的微妙法门却很少在化石记录中保存下来。

　　Rarely, but not never.

　　很少，不等于永远都没有。

　　That is why the recent discovery of a Jurassic ammonite with a shark's tooth embedded⁵ in its shell has excited palaeontologists.

　　这正是最近发现的一枚外壳中嵌有鲨鱼齿状物的侏罗纪鹦鹉螺化石令古生物学家兴奋的原因所在。

　　The ammonite in question, Orthaspidoceras, a species that thrived 155m years ago,

　　在1.55亿年前古鹦鹉螺是非常繁盛的物种，

　　was part of the collection of an amateur who did not realise the significance of what he had found.

　　讨论中的这枚鹦鹉螺化石是一个业余收藏家的收藏部分，这位收藏家没有意识到它的重大意义。

　　Romain Vullo of the University of Rennes,

　　然而，雷恩大学的罗曼?武洛意识到了，

　　however, did—and he has brought the discovery to the attention of the scientific world in the pages of Naturwissenschaften.

　　而且他已经借《自然科学》杂志成功地让这个发现受到科学界的注意。

　　Ammonites were both predators and prey.

　　古鹦鹉螺既是捕食者又是被掠食者。

　　They occupied a position in the Mesozoic oceans similar to that of modern squid.

　　他们在中生代海洋中占有一席之地，类似于现代的鱿鱼。

　　Like squid, they were swimming tentacled⁶ molluscs—a group called the cephalopods.

　　它们象鱿鱼一样是游动的触手软体动物，这类软体动物被称为头足类动物。

　　Unlike squid, though, they had protective shells.

　　不过，它们不象鱿鱼，它们有起保护作用的壳。

　　These shells were divided internally into gas-filled chambers⁸.

　　这些壳的内部划分成许多充气室。

　　The result had neutral buoyancy, allowing the animal to move by jet propulsion.

　　结果形成中和浮力，使动物能够借助喷气推进移动。

　　Modern pearly nautiluses, whose relationship to ammonites is much debated, have a similar arrangement.

　　现代的珍珠鹦鹉螺与古鹦鹉螺的关系备受争议，但它也有类似的结构安排。

　　What ammonites—or, at least, some of them—ate became clear earlier this year when an X-ray showed a small crustacean⁹ in the jaws¹⁰ of a species called Baculites.

　　古鹦鹉螺以什么为食在今年早些时候终于搞清楚了，X光显示了一个被称为Baculites物种的下颌，证明是小甲壳类动物。

　　But what ate ammonites has never been shown in such an unambiguous manner.

　　但是，人们还从来没有以这样一种毫不含糊的方式证明什么动物以古鹦鹉螺为食。

　　Some ammonite fossils have tooth marks that look as though they were made by huge reptilian¹¹ predators called mosasaurs.

　　有些鹦鹉螺化石上的齿痕看起来好像是由巨大的爬虫类捕食者沧龙留下的。

　　Some appear to have been attacked by the beaks¹² of other cephalopods.

　　有些看来像是其它头足类动物的嘴袭击过的痕迹。

　　And some seem to have been bitten by sharks.

　　有些似乎是被鲨鱼咬伤的。

　　On top of that, coprolites, as palaeontologists politely describe fossil faeces, have turned up with ammonite shells in them.

　　除此之外，被古生物学家委婉地形容成粪化石的粪便化石中也找到了古鹦鹉螺的壳。

　　Based on comparisons with modern evacua, these are probably from sharks.

　　根据与现代的排泄物相比较，这些化石可能都来自鲨鱼。

　　But which sharks?

　　但是是哪种鲨鱼呢？

　　Dr Vullo's ammonite nails one culprit.

　　武洛博士的鹦鹉螺化石锁定了一个罪魁祸首。

　　The tooth belongs to a species called Planohybodus.

　　这颗齿状物属于一个被称作Planohybodus的物种。

　　And that is a surprise.

　　这是一个惊喜。

　　Those modern sharks that eat shelled animals have robust¹³ teeth for crunching¹⁴ through hard exteriors¹⁵.

　　以有壳动物为食的那些现代鲨鱼都长着坚固耐用的牙齿，以便咬碎食物坚硬的外壳。

　　The teeth of Planohybodus, in contrast, were slender and pointed¹⁶—the sort usually associated with grasping and tearing at flesh.

　　相反，Planohybodus的牙齿细长而尖锐，就是通常让人联想到抓住并撕咬肉类的那种。

　　In a modern predator², that would indicate the habit of eating fish.

　　这可能意味着现代肉食动物有吃鱼的习惯。

　　That a shark with teeth like this would try to make a meal of an ammonite is, at first sight, odd.

　　长有这种牙齿的鲨鱼想吃掉古鹦鹉螺，乍一看太奇怪了。

　　But second thoughts provide a possible explanation.

　　但再三考虑就会想到一个可能的解释。

　　Ammonites' manoeuvrability would have depended crucially on their buoyancy control.

　　古鹦鹉螺的灵活性关键取决于其浮力控制。

　　Even a small puncture¹⁷ to the shell, which a pointed tooth would be well able to deliver,

　　即使在其外壳上有一个小小的穿刺，这点尖尖的牙齿驾轻就熟，

　　would let the water in and cause that control to vanish.

　　也会让水渗入，造成浮力控制的消失。

　　Since ammonites could not withdraw entirely¹⁸ into their shells for self-defence,

　　由于古鹦鹉螺不能完全缩回壳内自卫，那么就剩一个问题了，

　　it would then just be a question of dragging the creature out of its chamber⁷ in order to eat it.

　　即为了吃掉它而把这种动物从壳腔内拽出来。

　　And for that, sharp, pointed teeth are ideal.

　　对于这点，锐利的尖尖牙齿就十分理想了。

　　1.ecosystem n.生态系统

　　Water is the core of a healthy ecosystem.

　　水是维持生态系统良性循环的根本。

　　2.predator n.食肉动物；掠夺者

　　Young birds are very vulnerable to predators.

　　幼小的鸟易受食肉动物伤害。

　　3.prey n.牺牲者；被掠食者

　　She was easy prey for dishonest salesmen.

　　她很容易地让奸商敲了竹杠。

　　4.specialisation n.专门；专业化

　　Innovation and specialisation are more important.

　　创新和专业化更为重要。

　　5.preserve v.保护；保存；保持

　　It is highly important to preserve the environment.

　　保护自然环境至关重要。

1 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

2 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

3 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

4 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

5 embedded   

a.扎牢的

参考例句：

• an operation to remove glass that was embedded in his leg 取出扎入他腿部玻璃的手术
• He has embedded his name in the minds of millions of people. 他的名字铭刻在数百万人民心中。

6 tentacled   

有触角[触手]的

参考例句：

7 chamber   

n.房间，寝室；会议厅；议院；会所

参考例句：

• For many,the dentist's surgery remains a torture chamber.对许多人来说，牙医的治疗室一直是间受刑室。
• The chamber was ablaze with light.会议厅里灯火辉煌。

8 chambers   

n.房间( chamber的名词复数 )；（议会的）议院；卧室；会议厅

参考例句：

• The body will be removed into one of the cold storage chambers. 尸体将被移到一个冷冻间里。 来自《简明英汉词典》
• Mr Chambers's readable book concentrates on the middle passage: the time Ransome spent in Russia. Chambers先生的这本值得一看的书重点在中间：Ransome在俄国的那几年。 来自互联网

9 crustacean   

n.甲壳动物；adj.甲壳纲的

参考例句：

• Seafood is a valuable lobster crustacean section.名贵海珍品龙虾属甲壳科。
• The illustrious Cuvier did not perceive that a barnacle was a crustacean.大名鼎鼎的居维叶也未看出藤壶是一种甲壳动物。

10 jaws   

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 reptilian   

adj.（像）爬行动物的；（像）爬虫的；卑躬屈节的；卑鄙的n.两栖动物；卑劣的人

参考例句：

• The chick is ugly and almost reptilian in its appearance. 这只小鸡长得很丑，看起来几乎像个爬行动物。 来自辞典例句
• Being from Orion do Zetas contain DNA from the Reptilian race? 齐塔人是从猎户座而来，DNA来自爬虫族吗？ 来自互联网

12 beaks   

n.鸟嘴( beak的名词复数 )；鹰钩嘴；尖鼻子；掌权者

参考例句：

• Baby cockatoos will have black eyes and soft, almost flexible beaks. 雏鸟凤头鹦鹉黑色的眼睛是柔和的，嘴几乎是灵活的。 来自互联网
• Squid beaks are often found in the stomachs of sperm whales. 经常能在抹香鲸的胃里发现鱿鱼的嘴。 来自互联网

13 robust   

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。

14 crunching   

v.嘎吱嘎吱地咬嚼( crunch的现在分词 )；嘎吱作响；（快速大量地）处理信息；数字捣弄

参考例句：

• The horses were crunching their straw at their manger. 这些马在嘎吱嘎吱地吃槽里的草。 来自《简明英汉词典》
• The dog was crunching a bone. 狗正嘎吱嘎吱地嚼骨头。 来自《简明英汉词典》

15 exteriors   

n.外面( exterior的名词复数 )；外貌；户外景色图

参考例句：

• You mustn't judge people by their exteriors. 你不能以貌取人。 来自《简明英汉词典》
• Some artists only paint exteriors. 有些艺术家只画户外景色。 来自《简明英汉词典》

16 pointed   

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。

17 puncture   

n.刺孔，穿孔；v.刺穿，刺破

参考例句：

• Failure did not puncture my confidence.失败并没有挫伤我的信心。
• My bicycle had a puncture and needed patching up.我的自行车胎扎了个洞，需要修补。

18 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。