Hatala Kevin G, Gatesy Stephen M, Falkingham Peter L
Department of Biology, Chatham University, Pittsburgh, PA, USA.
Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, USA.
Nat Ecol Evol. 2023 Jan;7(1):32-41. doi: 10.1038/s41559-022-01929-2. Epub 2023 Jan 5.
The longitudinal arch of the human foot is viewed as a pivotal adaptation for bipedal walking and running. Fossil footprints from Laetoli, Tanzania, and Ileret, Kenya, are believed to provide direct evidence of longitudinally arched feet in hominins from the Pliocene and Pleistocene, respectively. We studied the dynamics of track formation using biplanar X-ray, three-dimensional animation and discrete element particle simulation. Here, we demonstrate that longitudinally arched footprints are false indicators of foot anatomy; instead they are generated through a specific pattern of foot kinematics that is characteristic of human walking. Analyses of fossil hominin tracks from Laetoli show only partial evidence of this walking style, with a similar heel strike but a different pattern of propulsion. The earliest known evidence for fully modern human-like bipedal kinematics comes from the early Pleistocene Ileret tracks, which were presumably made by members of the genus Homo. This result signals important differences in the foot kinematics recorded at Laetoli and Ileret and underscores an emerging picture of locomotor diversity within the hominin clade.
人类足部的纵弓被视为两足行走和奔跑的关键适应性特征。来自坦桑尼亚莱托利和肯尼亚伊莱雷特的化石足迹，分别被认为是上新世和更新世古人类存在纵弓足的直接证据。我们利用双平面X射线、三维动画和离散元颗粒模拟研究了足迹形成的动力学过程。在此，我们证明纵弓足迹并非足部解剖结构的真实指标；相反，它们是通过人类行走特有的特定足部运动模式产生的。对莱托利古人类化石足迹的分析仅显示了这种行走方式的部分证据，足跟触地方式相似，但推进模式不同。已知最早的完全现代人类似两足运动学的证据来自更新世早期的伊莱雷特足迹，这些足迹可能是由人属成员留下的。这一结果表明莱托利和伊莱雷特记录的足部运动学存在重要差异，并凸显了古人类分支中运动多样性的新图景。
