Revision of the subspecies ofAustralopithecus africanus (primates: Hominidae), including a new subspecies from the late pliocene of Ethiopia

Abstract

ABSTRACT. The subspecies of Australopithecus africanus DART, 1925 have been revised in a morphological and statistical analysis. Four subspecific names were previously proposed, but only one was found to be valid. The subspecies A. africanus transvaalensis (BROOM, 1936), from the Plio/Pleistocene of South Africa, cannot be sustained due to an insufficient sample, and is combined with the nominate race, A. a. africanus. The type of A. africanus afarensis TOBIAS, 1980 is a mistake in identification and not A. africanus, but a pongid. The population of A. africanus from the late Pliocene of Ethiopia does indeed represent a relatively small-toothed geographical race for which the name A.africanus aethiopicus was conditionally proposed; and the lectotype for it, A.L. 288-1, is not A. africanus, but the type of Homo antiquus FERGtrSON, 1984. The trinominal aethiopicus is thus unavailable for the Ethiopian race, which is redescribed as a new subspecies, A. africanus miodentatus n. ssp., and the mandible A.L. 266-1 is designated as the holotype.

A new species of the genusHomo (primates: Hominidae) from the Plio/Pleistocene of Koobi Fora, in Kenya

“…FERGUSON (1987b), however, demonstrated that it displays 21 secondary male sexual characteristics of the genus Homo not found in female H. habilis. Additional secondary male sexual features are the subangular sagittal contour of the cranium, and the overhang of the protruding occipital protuberance, which is especially pronounced in proportion to the small size of the occipital bone.…”

“…(TOBIAS, 1991). The reconstructed cranium Stw 53 from Sterkfontein, provisionally assigned to H. habilis (CLARKE, 1985a, b) was shown to belong to A. africanus (FERGUSON, 1989).…”

“…Its small endocranial capacity is a hominoid feature shared by the great apes, Australopithecus and Homo antiquus (FERGUSON, 1984(FERGUSON, , 1987. KNM-ER 1813 does not exhibit the apomorphic (derived), specialized masticatory apparatus of Australopithecus (anteroinferior inclination of the infraorbital region, lateral expansion of the temporal process of the zygomatic, and buccolingual expansion of the postcanine teeth).…”

“…Criteria for H. habilis are after LEAKEY et al (1964), TOBIAS (1991, and for A. antiquus after FERGUSON (1984).…”

“…Reassessment of the hominine cranium, KNM-ER 1813, from the Plio/Pleistocene of Koobi Fora, in Kenya, shows that it is not a small-brained, extreme female variant of H. habilis LEAKEY, TOBIAS, • NAPIER, 1964. Its cranial and dental morphology, morphometrics, and proportions do not conform with either H. habilis or 14. antiquus FERGUSON, 1984. On the basis of its distinctive morphological pattern and mensural gaps which distinguish it from H. habilis and H. antiquus, the cranium KNM-ER 1813 is described as a common variant representing a male of a small-brained, intermediate population linking H. habilis 1.83 Myr BP with H. antiquus 2.9 Myr BP, and a new paleospecies of the genus Homo. A key to the Homininae is provided and the phylogenetic relationship of KNM-ER 1813 to H. habilis and H. antiquus is discussed.…”