Convergent evolution in mechanical design of lamnid sharks and tunas
Convergent evolution in mechanical design of lamnid sharks and tunas
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DOI：
10.1038/nature02435
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发表时间：
2004-05-06
期刊：
影响因子：
64.8
通讯作者：
Shadwick, RE
中科院分区：
文献类型：
--
作者：
Donley, JM;Sepulveda, CA;Shadwick, RE
包括鲸鱼、鱼龙(1)和几种大型远洋鱼类(2)在内的几种不同的脊椎动物群体中“均匀”体型的进化支持了这样一种观点，即在脊椎动物进化过程中，物理和流体力学需求为优化运动的身体设计提供了重要的选择压力。人们认识到蓝鳍鲨（最著名的是大白鲨和灰鲭鲨）和金枪鱼在形态上的相似性，这导致了一种普遍的预期，即它们在功能设计上也有趋同；然而，目前还没有关于板状鲨运动系统力学性能的定量数据。在此，我们研究了鳍状鲨的游泳运动学、体内肌肉动力学和力传递系统的功能形态学，并表明远亲鳍状鲨和金枪鱼在体型和机械设计上的进化趋同远不止于皮肤深处；它延伸到肌腱结构的深处和推进运动的机械基础。我们不仅证明了蓝鳍鱼和金枪鱼的融合程度比以前所知的要大得多，而且它们在运动系统中也发展出了形态和功能上的适应，这与几乎所有其他鱼类都不同。
The evolution of 'thunniform' body shapes in several different groups of vertebrates, including whales, ichthyosaurs(1) and several species of large pelagic fishes(2) supports the view that physical and hydromechanical demands provided important selection pressures to optimize body design for locomotion during vertebrate evolution. Recognition of morphological similarities between lamnid sharks ( the most well known being the great white and the mako) and tunas has led to a general expectation that they also have converged in their functional design; however, no quantitative data exist on the mechanical performance of the locomotor system in lamnid sharks. Here we examine the swimming kinematics, in vivo muscle dynamics and functional morphology of the force-transmission system in a lamnid shark, and show that the evolutionary convergence in body shape and mechanical design between the distantly related lamnids and tunas is much more than skin deep; it extends to the depths of the myotendinous architecture and the mechanical basis for propulsive movements. We demonstrate that not only have lamnids and tunas converged to a much greater extent than previously known, but they have also developed morphological and functional adaptations in their locomotor systems that are unlike virtually all other fishes.