Cranial morphometry of early hominids: Facial region

Abstract

We report here on early hominid facial diversity, as part of a more extensive morphometric survey of cranial variability in Pliocene and early Pleistocene Hominidae. Univariate and multivariate techniques are used to summarise variation in facial proportions in South and East African hominids, and later Quaternary groups are included as comparators in order to scale the variation displayed. The results indicate that "robust" australopithecines have longer, broader faces than the "gracile" form, but that all australopithecine species show comparable degrees of facial projection. "Robust" crania are characterised by anteriorly situated, deep malar processes that slope forwards and downwards. Smaller hominid specimens, formally or informally assigned to Homo (H. habilis, KNM-ER 1813, etc.), have individual facial dimensions that usually fall within the range of Australopithecus africanus, but which in combination reveal a significantly different morphological pattern; SK 847 shows similarly hominine facial proportions, which differ significantly from those of A. robustus specimens from Swartkrans. KNM-ER 1470 possesses a facial pattern that is basically hominine, but which in some respects mimics that of "robust" australopithecines. Early specimens referred to H. erectus possess facial proportions that contrast markedly with those of other Villafranchian hominids and which suggest differing masticatory forces, possibly reflecting a shift in dietary niche. Overall the results indicate two broad patterns of facial proportions in Hominidae: one is characteristic of Pliocene/basal Pleistocene forms with opposite polarities represented by A. boisei and H. habilis; the other pattern, which typifies hominids from the later Lower Pleistocene onwards, is first found in specimens widely regarded as early representatives of H. erectus, but which differ in which certain respects from the face of later members of that species.

Humanity from African Naissance to Coming Millennia

“…Furthermore, SK 847 is clearly distinguished from H. erectus homologues in several features that are distinctive for that species in relation to other early Homo taxa. These morphological and morphometric characters lend support to conclusions reached by Grine et al ( , 1996 and by earlier studies (e.g., Howell, 1978;Bilsborough & Wood, 1988) that the affinities of SK 847 are with H. habilis rather than with H. erectus. These characters also tend to support suggestions that the closest affinities of SK 847 are with the Sterkfontein Member 5 cranium (Stw 53), which itself has been attributed to H. habilis.…”

“…Most notably, KNM-ER 1470 differs from the other four principally by virtue of its size, whereas there are significant shape differences between the smaller specimens from South Africa (SK 847 and Stw 53) and those from East Africa (OH 24 and KNM-ER 1813). Although the conclusions of Grine et al ( , 1996 differ from those of Walker (1981) and Clarke (1985), who drew attention to what they regarded as the striking overall similarity of SK 847 and the KNM-ER 3733 H. erectus cranium, they tend to corroborate the findings of Bilsborough & Wood (1988) on the affinities of SK 847. Their morphometric study led them to align SK 847 with the smaller early Homo crania from eastern Africa (KNM-ER 1813 and OH 24), although similarities with KNM-ER 1470 were also noted.…”

Natural history ofHomo erectus

“…The face is widest superiorly in China and Africa, and more similar in proportions to modern humans than is earlier Homo (Bilsborough and Wood, 1988;Wood and Richmond, 2000). The nasal bridge is relatively high.…”

“…It should be noted that the Daka calvaria groups with the Koobi Fora vaults in similar analyses (data not reported here). Except on the basis of size, these tests do not differentiate African from Asian forms (Antón, 2002a), although other methods suggest that the two may be metrically differentiable (Bilsborough and Wood, 1988). Although angular dimensions of the vault bones fail to distinguish African from Asian vaults, they do differentiate subadult from adult H. erectus specimens from all regions (Antón, 1997(Antón, , 2002aAntón and Leigh, 2003).…”

“…erectus, Homo habilis, and Homo sp. nov. (Clarke et al, 1970;Clarke and Howell, 1972;Howell, 1978;Olson, 1978;Bilsborough and Wood, 1988;Tobias, 1991;Grine, 1993Grine, , 2001Grine et al, 1993Grine et al, , 1996Grine et al, , 2003Clarke, 1994;Kimbel et al, 1997;Susman et al, 2001). The referred specimens come from Members 1-3 at Swartkrans, and thus should range in age from 1.8 -1.0 Ma (Susman et al, 2001).…”