Sixteen measurements of the talus have been taken on 334 tali of a total of eleven primate groups and several additional single individual specimens. Multivariate morphometric (canonical and generalized distance) analyses of these data in extant higher primates are presented and used to define the relative morphological positions of fossils of the genera Proconsul and Limnopithecus, of individual specimens from Kromdraai, Olduvai and Kiik-Koba (Homo neanderthalensis), and a group of specimens of Bronze Age man from Jericho.
Following preliminary studies the ultimate analysis suggests that the various extant arboreal primates examined fall within an envelope that is defined by Macaca together with various other Old World monkeys and extending in different directions to the extreme genera (a) Pongo, (b) Hylobates and (c) Ateles. This separation is thus one which defines generally quadrupedal monkeys and separates the various extreme arboreal locomotor modes of (a) acrobatic climbing and hanging, (b) richochetal brachiation and (c) prehensile-tailed arm-swinging and hanging, respectively. Man and the African apes are well separated both from each other and from this spectrum of arboreally adapted genera.
Bronze Age man from Jericho and Neandertal man from Kiik-Koba lie relatively close to the position for modern man although significantly separated from him. Limnopithecus, Proconsul, and the specimens from Kromdraai and Olduvai all lie within the envelope of arboreal species and specifically rather close to, although significantly different from, the orang-utan; they differ markedly from both man and the African apes.
The possibility exists that the resemblances of Proconsul and Limnopithecus relate to arboreal habitus in these species. The findings for the specimens from Kromdraai and Olduvai suggest either that the morphological resemblances to arboreal forms relate to a previous arboreal history for these species, or that bipedality is much less advanced or uniquely different from that displayed by Homo. It is not inconceivable that both conditions might apply.