Exploring morphological variation in hominid talar bones using geometric morphometric approaches

This thesis focused on the exploration of morphological variation in extinct and extant hominid talar bones through (semi)landmark-based geometric morphometric methods. The first section of this project analyzes sexual dimorphism in three modern human groups for which the sex is known from cemetery and municipal records. Shape, form and size variables have been investigated. Results shown that changes in size have the higher power in driving sexual differences in modern humans. The second section aims to evaluate both external and internal (trabecular bone) architecture of modern human tali related to populations with different lifestyle (nomadic vs. sedentary) and subsistence strategy. The goal is to determine changes related to different loadings during bipedal locomotion using both geometric morphometric and biomechanical methods. Overall, the results show differences between hunter-gatherers and sedentary groups, indicating that different locomotor behaviors of modern humans affect both internal and the external talar morphology. The third section investigate the morphological variability of extinct and extant hominid tali. The evolutionary timing and appearance of modern human-like features and their contributions to bipedal locomotion were evaluated on the talus as a whole, each articular facet separately, and multiple combinations of talar facets. We trace the evolutionary emergence of talar features in the human lineage that are linked to the biomechanical demands of bipedalism. We show that a more everted foot and stable medial midtarsal region are early adaptive modifications that coincide with the emergence of bipedalism, while a high medial longitudinal arch emerges comparatively more recently in the human evolutionary lineage In conclusion, this research points out that the talar morphology could be informative of intra- and inter specific anatomical variability in hominid taxa.