Demes B, Fleagle J G, Lemelin P
Department of Anatomical Sciences, State University of New York, Stony Brook 11794-8081, USA.
J Hum Evol. 1998 Apr;34(4):385-99. doi: 10.1006/jhev.1997.0203.
Although the skeletal correlates of vertical clinging and leaping behavior in primates have been studied in great detail, myological information on this locomotor group is not readily available. We here provide relative muscle mass data for the hindlimb of four prosimian leapers, representing indriids as well as the small-bodied tarsiers and galagos. Wet weights of all hindlimb muscles, with the exception of the intrinsic muscles of the foot, were determined. For comparative purposes muscle weights were also gathered for Varecia, an arboreal quadruped, and previously unpublished dry muscle weights of several monkeys are included as well. The specialized leapers are characterized by a predominance of muscles for hindlimb joint extensions. Indriids have larger hip extensors than ankle plantarflexors, whereas the galago and tarsier display the reverse condition. This dichotomy in relative muscle mass corresponds to a dichotomy in leaping kinematics, with indriids going through a greater range of movement at the hip joint and galagos and tarsiers at the ankle joint. However, the most striking result is the overwhelming dominance of the quadriceps femoris muscle in both groups. This suggests that power may be transferred from the knee and thigh to adjacent joints and segments. In contrast, quadrupedal primates have more extensor musculature at the hip, suggesting that the need for a short swing phase pendulum constrains muscle mass distribution within the limb of quadrupeds. Total muscle mass of the hindlimb as well as the mass of the propulsive muscles scale with body mass at exponents below the functional equivalence expectation. Larger-bodied leapers therefore have less muscle force available per unit body weight to be propelled than their smaller-bodied counterparts.
尽管灵长类动物垂直攀爬和跳跃行为的骨骼关联已得到详细研究，但关于这一运动群体的肌肉学信息却难以获取。我们在此提供了四种原猴亚目跳跃动物后肢的相对肌肉质量数据，包括大狐猴以及体型较小的跗猴和婴猴。除足部固有肌肉外，测定了所有后肢肌肉的湿重。为作比较，还收集了树栖四足动物马岛缟狸的肌肉重量，并且纳入了几只猴子此前未发表的干肌肉重量数据。这些特化的跳跃动物的特征是后肢关节伸展肌肉占主导。大狐猴的髋部伸肌比踝部跖屈肌更大，而婴猴和跗猴则呈现相反的情况。相对肌肉质量的这种二分法与跳跃运动学的二分法相对应，大狐猴在髋关节处的运动范围更大，而婴猴和跗猴在踝关节处的运动范围更大。然而，最显著的结果是两组动物中股四头肌都占据压倒性主导地位。这表明力量可能从膝盖和大腿传递到相邻的关节和节段。相比之下，四足灵长类动物在髋部有更多的伸肌组织，这表明对短摆动期钟摆的需求限制了四足动物肢体内部的肌肉质量分布。后肢的总肌肉质量以及推进肌肉的质量与体重的比例指数低于功能等效预期。因此，体型较大的跳跃动物每单位体重可用于推进的肌肉力量比体型较小的同类动物少。
