Kikuchi Yasuhiro, Hamada Yuzuru
Division of Human Anatomy and Biological Anthropology, Department of Anatomy and Physiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan.
Primates. 2009 Apr;50(2):169-83. doi: 10.1007/s10329-008-0120-3. Epub 2008 Dec 26.
We performed comparative analyses of four cross-sections of the distal radius and tibia in two species of macaque to clarify the relationships between bone morphology and locomotor type. The lengths of bones and five bone geometric properties in each section were examined and compared separately in both female and male Macaca mulatta and Macaca fascicularis. In M. mulatta, there were no significant gender-specific differences in either the radius or the tibia. In contrast, the radius and tibia of male M. fascicularis had greater geometric parameters in the 20% and 40% positions relative to the 5% and 10% positions from the distal end than those of their female counterparts. The radius and tibia of M. mulatta were relatively longer than those of M. fascicularis, and the sectional parameters of the tibia of M. mulatta were relatively larger than those of M. fascicularis. Standardization of the log-transformed bone length between the species revealed larger radial cortical bone areas in M. fascicularis. In contrast, there were minimal differences in the tibial cortical bone areas between the two species. This study suggests that the observed distinctions in bone geometry in female and male M. fascicularis may be due to gender-specific differences in the muscle weights of the forearm and calf, which may underlie the divergence in the leaping abilities of females and males of this species. Taken together, these results of interspecies comparisons may be related to the fact that arboreal primates such as M. fascicularis undergo compressive mechanical stress due to the forelimb lead that occurs as the animal descends a sloping trunk or bridges a tree gap downward, while terrestrial primates such as M. mulatta move on nearly flat substrates. Differences in fore- and hind-limb bone properties between the two species are discussed with regard to functional morphology and locomotor type.
我们对两种猕猴的桡骨远端和胫骨的四个横截面进行了比较分析，以阐明骨骼形态与运动类型之间的关系。分别对雌性和雄性恒河猴及食蟹猴的每一段骨骼长度和五个骨骼几何特性进行了检查和比较。在恒河猴中，桡骨和胫骨均未发现明显的性别差异。相比之下，雄性食蟹猴的桡骨和胫骨在相对于远端5%和10%位置的20%和40%位置处，其几何参数比雌性食蟹猴更大。恒河猴的桡骨和胫骨比食蟹猴的相对更长，且恒河猴胫骨的截面参数比食蟹猴的相对更大。对两物种间经对数转换后的骨骼长度进行标准化处理后发现，食蟹猴的桡骨皮质骨面积更大。相比之下，两物种间胫骨皮质骨面积的差异极小。本研究表明，观察到的雄性和雌性食蟹猴骨骼几何形状的差异可能是由于前臂和小腿肌肉重量的性别差异所致，这可能是该物种雌雄跳跃能力差异的基础。综上所述，这些种间比较结果可能与以下事实有关：像食蟹猴这样的树栖灵长类动物在沿倾斜树干下降或向下跨越树间间隙时，由于前肢领先而承受压缩机械应力，而像恒河猴这样的陆生灵长类动物在几乎平坦的地面上移动。我们从功能形态学和运动类型方面讨论了这两个物种前后肢骨骼特性的差异。
