Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna 40126, Italy; Department of Cultural Heritage, University of Bologna, Ravenna 48121, Italy.
Department of Anthropology, The Pennsylvania State University, State College, PA 16802, USA.
J Hum Evol. 2021 Dec;161:103093. doi: 10.1016/j.jhevol.2021.103093. Epub 2021 Nov 5.
Neanderthal foot bone proportions and morphology are mostly indistinguishable from those of Homo sapiens, with the exception of several distinct Neanderthal features in the talus. The biomechanical implications of these distinct talar features remain contentious, fueling debate around the adaptive meaning of this distinctiveness. With the aim of clarifying this controversy, we test phylogenetic and behavioral factors as possible contributors, comparing tali of 10 Neanderthals and 81 H. sapiens (Upper Paleolithic and Holocene hunter-gatherers, agriculturalists, and postindustrial group) along with the Clark Howell talus (Omo, Ethiopia). Variation in external talar structures was assessed through geometric morphometric methods, while bone volume fraction and degree of anisotropy were quantified in a subsample (n = 45). Finally, covariation between point clouds of site-specific trabecular variables and surface landmark coordinates was assessed. Our results show that although Neanderthal talar external and internal morphologies were distinct from those of H. sapiens groups, shape did not significantly covary with either bone volume fraction or degree of anisotropy, suggesting limited covariation between external and internal talar structures. Neanderthal external talar morphology reflects ancestral retentions, along with various adaptations to high levels of mobility correlated to their presumably unshod hunter-gatherer lifestyle. This pairs with their high site-specific trabecular bone volume fraction and anisotropy, suggesting intense and consistently oriented locomotor loading, respectively. Relative to H.sapiens, Neanderthals exhibit differences in the talocrural joint that are potentially attributable to cultural and locomotor behavior dissimilarity, a talonavicular joint that mixes ancestral and functional traits, and a derived subtalar joint that suggests a predisposition for a pronated foot during stance phase. Overall, Neanderthal talar variation is attributable to mobility strategy and phylogenesis, while H. sapiens talar variation results from the same factors plus footwear. Our results suggest that greater Neanderthal body mass and/or higher mechanical stress uniquely led to their habitually pronated foot posture.
尼安德特人的足部骨骼比例和形态与智人基本相同，但距骨有几个明显的尼安德特特征。这些明显距骨特征的生物力学意义仍存在争议，这引发了关于这种独特性的适应性意义的争论。为了澄清这一争议，我们将进化和行为因素作为可能的因素进行了比较，比较了 10 名尼安德特人和 81 名智人（旧石器时代晚期和全新世的狩猎采集者、农民和后工业化群体）以及克拉克·豪厄尔距骨（奥莫，埃塞俄比亚）的跟骨。通过几何形态测量方法评估了外部距骨结构的变异，同时在亚样本（n=45）中量化了骨体积分数和各向异性程度。最后，评估了特定部位骨小梁变量的点云与表面标志点坐标之间的协变关系。我们的研究结果表明，尽管尼安德特人的距骨外部和内部形态与智人组明显不同，但形态与骨体积分数或各向异性程度均无显著相关性，表明距骨内外结构之间的相关性有限。尼安德特人距骨的外部形态反映了祖先的保留，以及与他们可能不穿鞋的狩猎采集者生活方式相关的各种高机动性的适应。这与他们高的特定部位骨小梁的骨体积分数和各向异性程度相匹配，分别代表强烈和定向的运动负荷。与智人相比，尼安德特人在距小腿关节上存在差异，这可能归因于文化和运动行为的差异，距舟关节混合了祖先和功能特征，以及衍生的跗骨关节，这表明在站立阶段有足内翻的倾向。总体而言，尼安德特人的距骨变异归因于移动策略和系统发生，而智人的距骨变异则归因于相同的因素外加鞋类的影响。我们的研究结果表明，更大的尼安德特人体重和/或更高的机械应力独特地导致了他们习惯性的足内翻姿势。
