澳大利亚发现含有胚胎和脐带的鱼化石
2008-05-31
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| 鱼化石 |
澳大利亚发现含有胚胎和脐带的鱼化石
英国《金融时报》科学编辑克莱夫•库克森(Clive Cookson)报道
2008年5月30日 星期五
科学家在澳大利亚发现了一块不同寻常的鱼化石，化石上有一个大胚胎和脐带。据此，科学家将脊椎动物的性行为史追溯到距今3.8亿年前的泥盆纪(Devonian)。
这一发现于5月29日发表在《自然》(Nature)杂志上，是5月28日在从澳大利亚到伦敦的卫星连线中透露的，当时，在耗资2200万英镑对梅菲尔(Mayfair)历史悠久的皇家科学研究所(Royal Institution)进行翻修后，英国女皇重新开放了这所研究所。
墨尔本维多利亚博物馆(Museum Victoria)的约翰•朗(John Long)是该研究小组的负责人。他表示：“这无疑是化石界有史以来最不同寻常的发现之一。它不仅是人类首次发现的带有脐带的胚胎化石，还是有关生物活产记录的最古老已知例证。”
这块鲭鱼大小的化石被命名为“艾登堡母鱼”(Materpiscis Attenboroughi)，以纪念著名的自然学家大卫•艾登堡爵士(Sir David Attenborough)。它是盾皮鱼中的新种类。盾皮鱼身上覆有盔甲，统治泥盆纪海洋达7000万年。
“你们用我的名字命名如此神奇的生物，我感到万分荣幸，”艾登堡爵士向澳大利亚的古生物学家们表示。“你们发现和识别脐带的技术的确非同寻常。”
在此之前，显示动物体内受精的已知最古老化石是2亿年前的爬行动物的化石。
“在对样本进行研究后，我意识到，这是脊椎动物交配的最早证据——不仅仅是在水中产卵，乐趣的是性行为，”朗表示。“或者至少对雄性来说也许是有趣的。”一些雄性盾皮鱼化石显示出在交配期间用来抓住雌鱼的“紧握器”的证据。
研究小组后来发现了年代相近的另一种盾皮鱼，里面有三个较小的胚胎。这些化石来自西澳大利亚的Gogo 化石遗址——过去是古老礁石的一部分。
译者/管婧
阅读本文章英文,请点击 VERTEBRATE SEX SECRETS SURFACE IN FOSSIL FISH
VERTEBRATE SEX SECRETS SURFACE IN FOSSIL FISH
By Clive Cookson, Science Editor
Friday, May 30, 2008
Scientists have pushed back the history of vertebrate sex to the Devonian period 380m years ago, following the discovery in Australia of a remarkable fossilised fish containing a large embryo and umbilical cord.
The finding was revealed on the 28 May in a satellite link from Australia to London, when the Queen reopened the historic Royal Institution in Mayfair after a £22m renovation. It is published on the 29 May in the journal Nature.
John Long of Museum Victoria in Melbourne, who led the research team, said: “The discovery is certainly one of the most extraordinary fossil finds ever made. It is not only the first time ever that a fossil embryo has been found with an umbilical cord but it is also the oldest known example of any creature giving birth to live young.”
The mackerel-sized fossil was named Materpiscis Attenboroughi (Attenborough's mother fish) in honour of the famous naturalist Sir David Attenborough. It is a new species of placoderm, the type of armour-plated fish that dominated the Devonian oceans for 70m years.
“I am extremely flattered that you should give my name to such an astonishing creature,” Sir David told the Australian palaeontologists. “The skill with which you have revealed and identified the umbilical cord is really extraordinary.”
Previously, the oldest known fossils of animals in which the sperm fertilised eggs internally were reptiles dating back 200m years.
“It dawned on me after studying the specimen that this was the earliest evidence of vertebrates having sex by copulation – not just spawning in water, but sex that was fun,” said Prof Long. “Or it might have been fun for the male at least.” Some male placoderm fossils show evidence of “graspers” that held the female fish during copulation.
The team later discovered a placoderm of a different species but similar date, with three smaller embryos inside it. The fossils come from the Gogo formation in Western Australia, which was part of an ancient reef. |
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