par Berge, C.;Orban, Rosine ;Schmid, Patrick
Référence Journal of Human Evolution, 13, page (573-587)
Publication Publié, 1984
Article révisé par les pairs
Résumé : The pelvic cavities two australopithecines (Al 288, Sts 14) are studied biometrically in relation to a sample of extant human and non-human primates. Human obstetrical characteristics correspond to (1) a generic adaptation of the pelvic outlet which is opened ventrally to the ischial tuberosities, and (2) a sexual adaptation of the female inlet which is particularly enlarged between the hip joints and the pubic rami. The australopithecine pelvis presents most of these characteristics, but offers some significant dissimilarities notably an extreme biacetabular enlargement and a very specific morphology of the pubic region. A series of deductions leads us to suggest a Homo-like obstetrical mechanism for Australopithecus, characterized by the rotation and the flexion of the neonate, with fetal skull size similar to the one of the neonate chimpanzee, in the pelvic cavity. The constraints on the fetal skull are consequently as important as in human delivery. This means that the phenomenon of encephalization which took place during the evolution of the hominids could not be the result of an increase of the neonate cerebral capacity but was rather a consequence of neotenic change in growth-rhythm of the newborn. © 1994 Academic Press Inc. (London) Limited.