Origins of primate locomotion: Gait mechanics of the woolly opossum
Origins of primate locomotion: Gait mechanics of the woolly opossum
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DOI：
10.1002/ajpa.10048
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发表时间：
2002-07-01
影响因子：
2.8
通讯作者：
Lemelin, P
中科院分区：
文献类型：
--
作者：
Schmitt, D;Lemelin, P
灵长类动物的运动与其他哺乳动物的运动有三个基本的不同之处。在四足行走过程中，灵长类动物采用对角线顺序步态，前肢着地时手臂伸展较多，前肢相对于后肢的垂直衬底反作用力较小。人们普遍认为，灵长类动物不寻常的行走步态代表着对细小而灵活的树枝上运动的基本适应，并反映了前肢功能角色的重大变化。然而，几乎没有关于非灵长类树栖哺乳动物的数据来检验这一观点。为此，我们研究了负鼠(Caluromys Philander)的步态机制，这种有袋类动物在生态、行为和形态上都与小体原猴汇聚在一起。从录像带和力量记录中获得了三只成年负鼠在木制跑道和细杆上四足行走的脚步顺序、相对手臂伸展和最大垂直底物反作用力的数据。在两种基板上记录的所有步态中，毛负鼠总是采用对角顺序行走步态，手臂相对于身体水平轴线伸展超过90度，前肢上的垂直基板反作用力峰值显著低于后肢。负鼠是第一种表现出与灵长类完全相同的运动机制的非灵长类哺乳动物。灵长类和固定的细枝树栖有袋类动物之间的融合强烈表明，最早的灵长类动物进化出了细枝运动的步态专门化，这反映了前肢功能的重要变化。(C)2002年Wiley-Liss，Inc.
The locomotion of primates differs from that of other mammals in three fundamental ways. During quadrupedal walking, primates use diagonal sequence gaits, protract their arms more at forelimb touchdown, and experience lower vertical substrate reaction forces on their forelimbs relative to their hindlimbs. It is widely held that the unusual walking gaits of primates represent a basal adaptation for movement on thin, flexible branches and reflect a major change in the functional role of the forelimb. However, little data on nonprimate arboreal mammals exist to test this notion. To that end, we examined the gait mechanics of the woolly opossum (Caluromys philander), a marsupial convergent with small-bodied prosimians in ecology, behavior, and morphology. Data on the footfall sequence, relative arm protraction, and peak vertical substrate reaction forces were obtained from videotapes and force records for three adult woolly opossums walking quadrupedally on a wooden runway and a thin pole. For all steps recorded on both substrates, woolly opossums always used diagonal sequence walking gaits, protracted their arms beyond 90degrees relative to horizontal body axis, and experienced peak vertical substrate reaction forces on forelimbs that were significantly lower than on hindlimbs. The woolly opossum is the first nonprimate mammal to show locomotor mechanics that are identical to those of primates. This case of convergence between primates and a committed fine-branch, arboreal marsupial strongly implies that the earliest primates evolved gait specializations for fine-branch locomotion, which reflect important changes in forelimb function. (C) 2002 Wiley-Liss, Inc.