Knuckle‐walking and the evolution of hominoid hands
Knuckle‐walking and the evolution of hominoid hands
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指关节行走和类人猿手的进化
DOI：
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发表时间：
1967
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影响因子：
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通讯作者：
R. Tuttle
中科院分区：
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作者：
R. Tuttle
指关节行走是灵长类动物中非洲猿所特有的一种趾行运动方式。只有黑猩猩和大猩猩特别适合于支持重量的背部方面的中间指骨弯曲的手手指II-V。当被迫在地面上时，大多数猩猩会采取各种弯曲手部姿势之一，但它们不能用指关节行走。有些猩猩把他们的手放在手掌的姿势是不可能的非洲猿。非洲猿的指关节行走手和跖行脚在形态和适应性上都不同于现存猿类中与它们最近的亲戚Pongo。这些特征与向陆地运动的共同适应性转变有关，并支持将黑猩猩和大猩猩归为同一属。有人进一步提出，黑猩猩包括以下亚属：（a）黑猩猩亚属，包括黑猩猩和侏儒黑猩猩;（B）大猩猩亚属，包括山地和低地种群的大猩猩。
非洲猿很可能是从祖先的猩猩类分化而来的，后者特别适合将体重分布在森林树冠的末端树枝上。早期对地面运动的调整可能涉及拳头行走，后来演变为指关节行走。红毛猩猩继续适应在森林树冠层中进食和运动，他们的手和脚变得高度专门化，以适应四位数的移动。虽然黑猩猩保留了树栖觅食和筑巢的习惯，但它们通过陆地路线从一棵树迁移到另一棵树，栖息地的限制变得更少。在适应以地面植物为食的同时，大猩猩的体型增加到了这样一个程度，即它们在树上筑巢的频率低于黑猩猩和猩猩。
早期的原始人可能是从没有发展出对指关节行走的预期适应的猩猩类分化而来的，因此没有经过指关节行走的阶段。对陆地四足动物运动和静止姿态的最初调整可能包括掌移手姿势。它们的拇指可能已经发育得很好，以适应在树上攀爬时的抓握。选择压力的组合，以有效的地面运动支持和物体操纵进一步推进早期原始人类的手向现代人类的配置。
Knuckle-walking is a pattern of digitigrade locomotion unique to African apes among Primates. Only chimpanzees and gorillas are specially adapted for supporting weight on the dorsal aspects of middle phalanges of flexed hand digits II–V. When forced to the ground, most orangutans assume one of a variety of flexed hand postures, but they cannot knuckle-walk. Some orangutans place their hands in palmigrade postures which are impossible to African apes. The knuckle-walking hands and plantigrade feet of African apes are both morphologically and adaptively distinct from those of Pongo, their nearest relative among extant apes. These features are associated with a common adaptive shift to terrestrial locomotion and support placing chimpanzees and gorillas in the same genus Pan. It is further suggested than Pan comprises the subgenera (a) Pan, including P. troglodytes and pygmy chimpanzees, and (b) Gorilla, including mountain and lowland populations of P. gorilla.
African apes probably diverged from ancestral pongids that were specially adapted for distributing their weight in terminal branches of the forest canopy. Early adjustments to terrestrial locomotion may have involved fist-walking which later evolved into knuckle-walking. Orangutans continued to adapt to feeding and locomotion in the forest canopy and their hands and feet became highly specialized for four-digit prehension. Although chimpanzees retained arboreal feeding and nesting habits, they moved from tree to tree by terrestrial routes and became less restricted in habitat. While adapting to a diet of ground plants gorillas increased in size to the point that arboreal nesting is less frequent among them than among chimpanzees and orangutans.
Early hominids probably diverged from pongids that had not developed prospective adaptations to knuckle-walking, and therefore did not evolve through a knuckle-walking stage. Initial adjustments to terrestrial quadrupedal locomotion and resting stance probably included palmigrade hand posturing. Their thumbs may have been already well developed as an adaptation for grasping during arboreal climbing. A combination of selection pressures for efficient terrestrial locomotor support and for object manipulation further advanced early hominid hands toward modern human configuration.