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首页> 外文期刊>American Zoologist >Functional microanatomy of the feather-bearing integument: implications for the evolution of birds and avian flight
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Functional microanatomy of the feather-bearing integument: implications for the evolution of birds and avian flight

机译：羽毛覆盖物的功能微观解剖：对鸟类和鸟类飞行进化的影响

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摘要

A selective regime favoring a streamlining of body contours and surfaces is proposed as having been instrumental in driving the morphological and functional transformations of an unfeathered reptilian integument into a featherbearing avian one. This hypothesis is consistent with a new, structurally and functionally coherent analysis of the micro anatomy of the avian feather-bearing integument as a complex, integrated organ system that includes an intricate, hydraulic skeleto-muscular apparatus of the feathers, a dermo-subcutaneous muscle system of the integument, and a subcutaneous hydraulic skeletal system formed by fat bodies. Key elements of the evidence supporting the new hypothesis are (1) the presence of depressor feather muscles that are not needed as antagonists for the erector feather muscles, but can counteract external forces, such as air currents; (2) the fact that the highly intricate feather-bearing integument represents a machinery to move feathers or to stabilize them against external forces; (3) the crucial role of the coat of feathers in streamlining the body contours and surfaces of birds; (4) the aerodynamic role of feathers as pressure and turbulence sensors and as controllable temporary tnrbulators; and (5) the critical role that a streamlined body plays in avian flight and is likely to have played in the evolutionary transformations from ecologically and locomotorily versatile quadrupedal reptiles to volant bipedal birds without passing through parachuting or gliding stages. These transformations are likely to have occurred more than once. The ancestral birds were probably small, arboreal, hopping, and using flap-bounding, or intermittent bounding, flight.
机译：有人提出了一种有利于精简身体轮廓和表面的选择性方案，因为这种方案有助于推动无羽化的爬虫类动物外皮转变为带有羽毛的禽类的形态和功能转变。该假设与对禽羽毛外皮微观结构的新的，结构上和功能上一致的分析是一致的，该分析是一个复杂的，集成的器官系统，其中包括羽毛的复杂的液压骨骼肌设备，皮下皮下肌肉皮膜系统，以及由脂肪体形成的皮下水力骨骼系统。支持新假设的证据的关键要素是：（1）不需要压抑羽毛肌作为竖立羽毛肌的拮抗剂，但可以抵消外力，例如气流; （2）高度复杂的带有羽毛的外皮是一种移动羽毛或稳定羽毛抵抗外力的机制; （3）羽毛外套在简化鸟类的身体轮廓和表面中的关键作用; （4）羽毛作为压力和湍流传感器以及可控的临时扰动器的空气动力学作用; （5）精简的身体在鸟类飞行中起着至关重要的作用，并且可能在不经过跳伞或滑翔阶段的过程中，从生态学和运动学上通用的四足动物爬行动物到雄伟的两足动物鸟类的进化转变中发挥了重要作用。这些转变可能已经发生了不止一次。祖先的鸟类可能很小，树栖，跳动，并使用襟翼包围或间歇性包围飞行。

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