A 3D form comparative analysis of the Neandertal glenoid fossa in the context of the genus Homo

摘要

Morphological differences between the Neandertal and modern human glenoid fossa are mostly attributed to functional factors. However, the intimate relationship between the pectoral girdle and the shape of the thorax on which it rests calls for a structural analysis of the morphology of the glenoid fossa. Using both 3D Geometric Morphometric techniques and classical osteometry we carry out an analysis of the morphology of Neandertal scapular glenoid fossa, considering the effects that independent parameters such as allometry, sexual dimorphism and laterality could exert on the glenoid fossa shape. We also discuss how the morphological configuration of the thorax together with other functional factors could explain some of the differences between Neandertals and H. sapiens, and we assess the morphological evolution of this structure in the context of the genus Homo. To this end, 3DGM methods were applied in a comparative framework including the new SD-2101 + specimen from the Sidron site (Spain) dated to 49,000 years ago, other Neandertal, Homo sapiens, KNM-WT 15000 (Homo ergaster/erectus) and Pan troglodytes specimens. A total of 75 sliding semilandmarks were used to collect the morphology of the glenoid fossa. Morphological comparison and variability were assessed through principal component analysis. Our results confirm the metric and morphological features of the Neandertal scapular glenoid fossa and point to a multifactorial effect in the glenoid morphology. We also detect a morphological trait of the Neandertal glenoid fossa that has not been reported previously: the projection of the upper part of the ventral border shared with modern humans and influenced by structural factors related to the configuration of the rib cage and shoulder. These results are consistent with the evolutionary framework of the hominin glenoid fossa, with some morphological changes being caused by functional factors, and others by structural factors such as the configuration of the thorax. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.