The pelvic fin and girdle of Panderichthys and the origin of tetrapod locomotion
The pelvic fin and girdle of Panderichthys and the origin of tetrapod locomotion
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DOI：
10.1038/nature04119
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发表时间：
2005-12-22
期刊：
影响因子：
64.8
通讯作者：
Boisvert, CA
中科院分区：
文献类型：
--
作者：
Boisvert, CA
在脊椎动物向陆地过渡的过程中，最显著的转变之一是鳍向四肢的转变。这一转变不仅涉及形态学上的新变化（趾、骶骨），还涉及运动优势从胸鳍向骨盆附件的转移（1）。尽管它的重要性，从腹鳍到后肢的转变是最少研究和最少记录的部分，这是由骨鳞目的Eusthenopteron和早期四足动物鱼石螈和鱼石螈，但没有直接阐明任何中间形式。Panderichthys是最近的四足动物亲属，目前有完整的化石（2），但它的腹鳍骨骼尚未被描述。在这里，我提出了唯一已知的关节腹鳍内骨骼和相关的部分骨盆的潘德里科。腹鳍带甚至比骨鳞真鳍龙更不像四足动物（3），但腹鳍内骨骼与基础四足动物共享衍生特征，尽管它比潘德里科的胸鳍更原始（4，5）。四足动物运动的进化似乎经历了一个身体弯曲推进的阶段，在这个阶段中，腹鳍起到了相对较小的锚定作用，在Panderichthys和Eustega之间的间隔中出现了后肢动力推进。
One of the most marked transformations in the vertebrate transition to land was that of fins to limbs. This transformation involved not only the generation of morphological novelties ( digits, sacrum) but also a shift in locomotory dominance from the pectoral to the pelvic appendage(1). Despite its importance, the transformation from pelvic fin to hindlimb is the least studied and least well-documented part of this transformation, which is bracketed by the osteolepiform Eusthenopteron and the early tetrapods Ichthyostega and Acanthostega, but is not directly illuminated by any intermediate form. Panderichthys is the closest tetrapod relative currently represented by complete fossils(2), but its pelvic fin skeleton has not been described. Here, I present the only known articulated pelvic fin endoskeleton and associated partial pelvis of Panderichthys. The pelvic girdle is even less tetrapod-like than that of the osteolepiform Eusthenopteron(3), but the pelvic fin endoskeleton shares derived characteristics with basal tetrapods despite being more primitive than the pectoral fin of Panderichthys(4,5). The evolution of tetrapod locomotion appears to have passed through a stage of body-flexion propulsion, in which the pelvic fins played a relatively minor anchoring part, before the emergence of hindlimb-powered propulsion in the interval between Panderichthys and Acanthostega.