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, Sagamihara, Kanagawa, 252-5201, Japan.
Sci Rep. 2021 Dec 15;11(1):24063. doi: 10.1038/s41598-021-03429-y.
To reconstruct locomotor behaviors of fossil hominins and understand the evolution of bipedal locomotion in the human lineage, it is important to clarify the functional morphology of the talar trochlea in humans and extant great apes. Therefore, the present study aimed to investigate the interspecific-differences of the talar trochlear morphology among humans, chimpanzees, gorillas, and orangutans by means of cone frustum approximation to calculate an apical angle and geometric morphometrics for detailed variability in the shape of the talar trochlea. The apical angles in gorillas and orangutans were significantly greater than those in humans and chimpanzees, but no statistical difference was observed between humans and chimpanzees, indicating that the apical angle did not necessarily correspond with the degree of arboreality in hominoids. The geometric morphometrics revealed clear interspecific differences in the trochlear morphology, but no clear association between the morphological characteristics of the trochlea and locomotor behavior was observed. The morphology of the trochlea may not be a distinct skeletal correlate of locomotor behavior, possibly because the morphology is determined not only by locomotor behavior, but also by other factors such as phylogeny and body size.
为了重建古人类的运动行为，并了解人类谱系中双足运动的进化，阐明人类和现生大猿距骨滑车的功能形态学非常重要。因此，本研究旨在通过圆锥体近似法计算顶点角度，并进行详细的距骨滑车形态的几何形态测量，来研究人类、黑猩猩、大猩猩和猩猩之间距骨滑车形态的种间差异。大猩猩和猩猩的顶点角度明显大于人类和黑猩猩，但人类和黑猩猩之间没有统计学差异，这表明顶点角度不一定与类人猿的树栖程度相对应。几何形态测量学揭示了滑车形态的明显种间差异，但没有观察到滑车形态与运动行为之间存在明显的关联。滑车的形态可能不是运动行为的一个明显的骨骼关联，这可能是因为形态不仅由运动行为决定，还受到其他因素的影响，如系统发育和体型。
