Newborn Size and Pelvic Dimensions of Australopithecus

  title={Newborn Size and Pelvic Dimensions of Australopithecus},
  author={W. Leutenegger},
IN mammals construction of the pelvis not only reflects functional adaptations to certain modes of locomotion but also depends on maternal-foetal size relationships. Therefore, information about body weight and head size of newborn Australopithecus in relation to the size of the female pelvic inlet is of evolutionary significance with respect to the adaptation of hominids to bipedalism. 
Functional aspects of pelvic morphology in simian Primates
An estimate of the degree and interaction of selective forces acting on the pelvis of simian Primates which result from maternal-fetal size relationships and their interaction with selective forces resulting from locomotory functions in Australopithecus africanus is given to further elucidate the problem of the evolution of hominid bipedalism. Expand
Some implications of relative biomechanical neck length in hominid femora
Fossil hominids through the middle Pleistocene appear to have relatively longer femur necks than expected, excepting the two small australopithecine females, and it is suggested that this variation results from smaller crania at birth in the fossils. Expand
Bipedalism and human birth: The obstetrical dilemma revisited
This obstetrical dilemma was solved by delivery of the fetus at a much earlier stage of development because adaptation to bipedal locomotion decreased the size of the bony birth‐canal at the same time that the exigencies of tool use selected for larger brains. Expand
Size and shape of the australopithecine pelvic bone
The aim of this paper is to present results of a new morphometric analysis of australopithecine pelvic bones to try to understand the reasons of this situation, it appears that australipithecines exhibit the same overall architectural pattern as extant humans, the hominid pattern, just as all African apes also exhibit thesame pongid pattern. Expand
Allometry of neonatal size in eutherian mammals
The scaling of neonatal size in eutherian mammals and primates in particular is investigated and it is demonstrated that neonatal weight in 15 species of anthropoid primates scales at a power of maternal weight of 0.70. Expand
Neonatal brain size and neurocranial dimensions in Pliocene hominids: implications for obstetrics
It is argued that (1) the chimpanzee model is no longer tenable, and (2) they also would have been smaller than corresponding female pelvic dimensions, i.e. obstetrical constraints were absent in Pliocene hominids. Expand
Obstetrical interpretation of the Australopithecine pelvic cavity
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 is suggested. Expand
Climate and body shape in hominid evolution
It is shown here that this increase in relative linearity of the body with an increase in body size is consistent with basic thermoregulatory principles, and constraints on absolute body breadth may have contributed to the evolution of the rotational birth process and secondary altriciality with increased body and brain size inHomo erectus. Expand
Early Hominid Postcrania and Locomotor Adaptations
The locomotor system of modern man is a complex and unique adaptation, and the evolutionary origin and history of bipedalism are of fundamental importance in understanding the pattern of humanExpand
The first bipeds: a comparison of theA. afarensis and A. africanus postcranium and implications for the evolution of bipedalism
Although the postcranium of Australopithecus africanus is uniquely different from all extant hominoids, it is nearly identical to A. afarensis, which implies that natural selection was maintaining a structural adaptation for locomotor behaviors unlike those seen in any extant Hominoids. Expand


New Endocranial Values for the Australopithecines
There are substantial differences between the determinations of endocranial volumes and those previously published in australopithecines. Expand
Sex differences in the pelves of primates.
  • A. H. Schultz
  • Medicine
  • American journal of physical anthropology
  • 1949