HOMO HABILIS

extinct species of early hominid that inhabited parts of sub-Saharan Africa about 2 million to 1.5 million years ago. Considerable disagreement exists concerning the evolutionary place of this species, but H. habilis is generally accepted as the earliest member of the genus Homo, following Australopithecus and preceding H. erectus. The remains of H. habilis were first discovered in 1959 and 1960 at Olduvai Gorge in northern Tanzania. After more specimens were discovered, it was recognized that these fossils represented a species anatomically different from Australopithecus. In 1964, L.S.B. Leakey, Philip Tobias, and John Napier named this species Homo habilis, meaning able (or handy) man. The increased cranial capacity and reduced molar and premolar tooth size seemed to foreshadow trends seen in H. erectus and later humans. Since 1960 additional discoveries have been made, including fossils found in the Kooba Fora region of northern Kenya and, perhaps, at Swartkrans and at Sterkfontein in South Arica. The remains of H. habilis have provided a fair amount of knowledge about the anatomy of this hominid. Based on various skull fragments, researchers have estimated that the cranial capacity of H. habilis ranged from slightly more than 500 to nearly 800 cubic cm (about 30 to 50 cubic inches). Facial proportions vary substantially among individuals, with some specimens more closely resembling Australopithecus and some H. erectus. Limb bones suggest that H. habilis walked efficiently bipedally, and the fossil of a hand suggests that H. habilis was capable of precise manipulation of objects. Crude tools found along with the remains of H. habilis provide further evidence that this species could shape stone. Some anthropologists have argued that H. habilis could also communicate verbally, but the limited archaeological record makes this claim difficult to support. The wide range of variance in specific anatomical features, particularly cranial size, has led some researchers to conclude that these remains represent two species. One theory incorporating two taxa classifies individuals with smaller crania as a species of gracile australopithecines and only individuals with larger crania as Homo. Other researchers suggest that these remains represent two species of Homo, only one of which could have been the immediate predecessor to H. erectus. See also Homo erectus; Australopithecus.