Size- and locomotion-related aspects of hominid and anthropoid pelves: An osteometrical multivariate analysis

Two multivariate methods — the logarithmic principal component analysis (LPCA), and the logarithmic factorial analysis (LFA) — have been used tocompare the hip bone proportions of hominoids biometrically. The results have shown that size effects among apes and hominids interact to a centain extent with locomotor specializations, which are related to the attainment of more or less terrestrial behaviors. The pelvic morphology of great apes (Pongo, Pan, Gorilla) has retained numerous morphological traits — such as a gracile and elongated hip bone —, which were inherited from common adaptations to arboreal locomotion. In spite of these common traits, the African pongids (Pan, Gorilla) present two very different pelvic morphologies corresponding to two adaptative modes of terrestrial quadrupedalism. The hip bone of humans is proportionnally short and robust, most particularly at the level of its axial part. These characteristics, as well as the whole pelvic proportions, clearly indicate that gravitational forces exert a strong pressure on the pelvic walls during bipedalism. Among hominids, the transition from an australopithecine-like pelvic pattern to a human-like one corresponds to an increase of loading constraints on the hip jiont. This seems to indicate an evident change in locomotor behavior. Progression apparently became exclusively terrestrial with the genusHomo.