The basicranial axis in certain fossil hominoids

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Abstract
The publication of accurate sagittal diagrams of the skulls of certain australopithecine fossils has permitted biometrical comparison of their basicranial axis, together with its anterior extension to the nasion, its posterior extension to the opisthion and the two associated angles, to be made with the corresponding regions in monkeys, apes and Man.Univariate study has shown that after appropriate correction for differences in overall size, each of these quantities effects discrimination between certain extant primate groups. All can be separated if the measurements are taken seriatim. Australopithecus transvaalensis and Australopithecus boisei are thus distinguished both from extant groups and from each other.Multivariate study (generalized distances and canonical coordinates) shows that both these fossils are distinct from all living groups which, in turn, are separate from one another.Such unique characterization of the basicranial axis in the Australopithecinae parallels taxonomic distinctiveness already established in respect of their teeth, their occipital condyles and several regions of their postcranial skeleton.