Behavioral evidence for the evolution of walking and bounding before terrestriality in sarcopterygian fishes
Behavioral evidence for the evolution of walking and bounding before terrestriality in sarcopterygian fishes
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DOI：
10.1073/pnas.1118669109
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发表时间：
2011-12-27
影响因子：
11.1
通讯作者：
Hale, Melina E.
中科院分区：
文献类型：
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作者：
King, Heather M.;Shubin, Neil H.;Hale, Melina E.
四足动物在泥盆纪从肉鳍鱼类进化而来，是第一批定居陆地的脊椎动物。这种转变的运动组成部分可以分为四个主要事件：陆地性，指状肢体的起源，基于固体基质的运动，以及使用骨盆附件作为主要推进器的交替步态。作为四足动物的姐妹群，肺鱼是一个形态学和遗传学上相关的肌翅目分类单元，用于理解这些事件发生的顺序。我们发现，一个物种的非洲肺鱼（Protopterus annectens）使用一系列的骨盆鳍驱动，四足动物一样的步态，包括行走和跳跃，在水生环境中，尽管有衍生的肢体内骨骼和小，肌肉支撑骨盆。令人惊讶的是，鉴于这些形态特征，P. annectens还使用腹鳍将其身体从基底上抬起，这种能力被认为是四足动物的创新。我们的研究结果表明，四足动物运动的一些基本特征，包括骨盆肢步态模式和基板协会，可能出现在sarcoprophans的起源之前，digited四肢或terrestriality。因此，一些非指状泥盆纪化石足迹的归属四肢四足动物可能需要重新审视。
Tetrapods evolved from sarcopterygian fishes in the Devonian and were the first vertebrates to colonize land. The locomotor component of this transition can be divided into four major events: terrestriality, the origins of digited limbs, solid substrate-based locomotion, and alternating gaits that use pelvic appendages as major propulsors. As the sister group to tetrapods, lungfish are a morphologically and phylogenetically relevant sarcopterygian taxon for understanding the order in which these events occurred. We found that a species of African lungfish (Protopterus annectens) uses a range of pelvic fin-driven, tetrapod-like gaits, including walking and bounding, in an aquatic environment, despite having a derived limb endoskeleton and primitively small, muscularly supported pelvis. Surprisingly, given these morphological traits, P. annectens also lifts its body clear of the substrate using its pelvic fins, an ability thought to be a tetrapod innovation. Our findings suggest that some fundamental features of tetrapod locomotion, including pelvic limb gait patterns and substrate association, probably arose in sarcopterygians before the origin of digited limbs or terrestriality. It follows that the attribution of some of the nondigited Devonian fossil track-ways to limbed tetrapods may need to be revisited.