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词汇 Acanthostega
分类 英语词汇 英语翻译词典
释义

Acanthostega

中文百科

棘螈

棘螈的复原图。
棘螈的化石。
棘螈的头骨化石。

棘螈（学名Acanthostega），又名棘鱼石螈，是一种已灭绝的四足总纲动物，是最初有明显四肢的脊椎动物。牠出现于约3亿6000万年前的上泥盆纪，是肉鳍鱼类与第一种能在陆地上行走的四足动物的中间体。

英语百科

Acanthostega 棘螈

Model reconstruction of Acanthostega at State Museum of Natural History in Stuttgart, Germany
Skull of Acanthostega gunnari.
In Late Devonian vertebrate speciation, descendants of pelagic lobe-finned fish – like Eusthenopteron – exhibited a sequence of adaptations: *Panderichthys, suited to muddy shallows; *Tiktaalik with limb-like fins that could take it onto land; *Stem-tetrapods in weed-filled swamps, such as: **Acanthostega which had feet with eight digits, **Ichthyostega with limbs. Descendants also included pelagic lobe-finned fish such as coelacanth species.

Acanthostega (meaning spiny roof) is an extinct genus of stem-tetrapod, among the first vertebrate animals to have recognizable limbs. It appeared in the late Devonian period (Famennian age) about 365 million years ago, and was anatomically intermediate between lobe-finned fishes and those that were fully capable of coming onto land.
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