Australopithecine

Abstract: Human biological and cultural evolution are closely linked to technological innovations. Direct evidence for tool manufacture and use is absent before 2.5 million years ago (Ma), so reconstructions of australopithecine technology are based mainly on the behavior and anatomy of chimpanzees. Stone tool technology, robust australopithecines, and the genus Homo appeared almost simultaneously 2.5 Ma. Once this adaptive threshold was crossed, technological evolution was accompanied by increased brain size, population size, and geographical range. Aspects of behavior, economy, mental capacities, neurological functions, the origin of grammatical language, and social and symbolic systems have been inferred from the archaeological record of Paleolithic technology.

Abstract: on the west side of Lake Natron, some fifty miles north-east of Olduvai Gorge. Initial exploration of this area was carried out under the leadership of my son, Richard Leakey, who was later joined by Mr. Glynn Isaac, who took charge of the scientific side of the work. Mrs. Isaac, Mr. Richard Rowe and Philip Leakey also took part, as well as a number of our African staff. On January 11 one of our African staff, Mr. Kamoya Kimeu, located a magnificient fossil hominid jaw in situ (see Figs. 6 and 7). This jaw, unlike specimens (A), (B), (C) and (D) here, represents an unmistakable australopithecine and provides, for the first time, a mandible representing this sub-family from East Africa. It will be recalled that in earlier notes in Nature and elsewhere, we have stressed the fact that the juvenile and the other fossil remains from site F.L.K.N.N. I, found in 1960, did not represent an australopithecine such as Australopithecus (Zinianthropus) boisei, but were wholly distinct and different. It was stated that these must be thought of as representing a contemporary and primitive hominine branch of the Hominidae. We refrained from giving a scientific name to the material from site F.L.K.N.N. I-the juvenile and the female-together with other specimens representing the same type (the molar tooth from site M.K. I) until there were better data on which to decide just where to place this type of hominid in the taxonomic sequence. The new material found in 1963 makes it possible to draw conclusions and to give a diagnosis for a new species of the genus Homo. This diagnosis and a preliminary description by Leakey, Tobias and Napier follow this article.

Abstract: We review the evolution of human bipedal locomotion with a particular emphasis on the evolution of the foot. We begin in the early twentieth century and focus particularly on hypotheses of an ape-like ancestor for humans and human bipedal locomotion put forward by a succession of Gregory, Keith, Morton and Schultz. We give consideration to Morton's (1935) synthesis of foot evolution, in which he argues that the foot of the common ancestor of modern humans and the African apes would be intermediate between the foot of Pan and Hylobates whereas the foot of a hypothetical early hominin would be intermediate between that of a gorilla and a modern human. From this base rooted in comparative anatomy of living primates we trace changing ideas about the evolution of human bipedalism as increasing amounts of postcranial fossil material were discovered. Attention is given to the work of John Napier and John Robinson who were pioneers in the interpretation of Plio-Pleistocene hominin skeletons in the 1960s. This is the period when the wealth of evidence from the southern African australopithecine sites was beginning to be appreciated and Olduvai Gorge was revealing its first evidence for Homo habilis. In more recent years, the discovery of the Laetoli footprint trail, the AL 288-1 (A. afarensis) skeleton, the wealth of postcranial material from Koobi Fora, the Nariokotome Homo ergaster skeleton, Little Foot (Stw 573) from Sterkfontein in South Africa, and more recently tantalizing material assigned to the new and very early taxa Orrorin tugenensis, Ardipithecus ramidus and Sahelanthropus tchadensis has fuelled debate and speculation. The varying interpretations based on this material, together with changing theoretical insights and analytical approaches, is discussed and assessed in the context of new three-dimensional morphometric analyses of australopithecine and Homo foot bones, suggesting that there may have been greater diversity in human bipedalism in the earlier phases of our evolutionary history than previously suspected.