Laboratory of Human Evolutionary Biomechanics, Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
Laboratory of Anatomy, School of Veterinary Medicine, Azabu University, Kanagawa, 252-0206, Japan.
Sci Rep. 2021 Oct 22;11(1):20889. doi: 10.1038/s41598-021-99942-1.
Investigating the morphological differences of the calcaneus in humans and great apes is crucial for reconstructing locomotor repertories of fossil hominins. However, morphological variations in the calcaneus of the great apes (chimpanzees, gorillas, and orangutans) have not been sufficiently studied. This study aims to clarify variations in calcaneal morphology among great apes based on three-dimensional geometric morphometrics. A total of 556 landmarks and semilandmarks were placed on the calcaneal surface to calculate the principal components of shape variations among specimens. Clear interspecific differences in calcaneal morphology were extracted, corresponding to the degree of arboreality of the three species. The most arboreal orangutans possessed comparatively more slender calcaneal tuberosity and deeper pivot region of the cuboid articular surface than chimpanzees and gorillas. However, the most terrestrial gorillas exhibited longer lever arm of the triceps surae muscle, larger peroneal trochlea, more concave plantar surface, more inverted calcaneal tuberosity, more everted cuboid articular surface, and more prominent plantar process than the orangutans and chimpanzees. These interspecific differences possibly reflect the functional adaptation of the calcaneus to locomotor behavior in great apes. Such information might be useful for inferring foot functions and reconstructing the locomotion of fossil hominoids and hominids.
研究人类和大型猿类跟骨的形态差异对于重建古人类的运动模式至关重要。然而，大型猿类（黑猩猩、大猩猩和猩猩）跟骨的形态变化尚未得到充分研究。本研究旨在基于三维几何形态测量学，阐明大型猿类跟骨形态的变化。在跟骨表面共放置了 556 个标志点和半标志点，以计算标本之间形状变化的主成分。提取出了明显的种间跟骨形态差异，与三种物种的树栖程度相对应。最具树栖性的猩猩跟骨的跟结节相对更细长，骰骨关节面的枢轴区更深，而与黑猩猩和大猩猩相比。然而，最具陆地性的大猩猩与猩猩和黑猩猩相比，具有更长的比目鱼肌的杠杆臂、更大的外踝滑车、更凹的足底表面、更倒置的跟结节、更外展的骰骨关节面和更突出的足底突。这些种间差异可能反映了跟骨对大型猿类运动行为的功能适应。这些信息可能有助于推断足部功能和重建古人类和古人类的运动模式。
