Ethiopian Finds and Feuds
Bower, Bruce, Science News
Separate investigations in Ethiopia last year uncovered the oldest firmly dated hominid stone tools and a largely complete Australopithecus boisei skull. But a dispute between two research teams over the boundaries of their excavation areas in Ethiopia erupted at the meeting into public charges of unethical conduct and vigorous denials of the accusation.
The controversy concerns an area known as Gona, which lies next to the Hadar geologic formation. Hadar excavations have yielded 3- to 4-million-year-old fossils of A. afarensis, including the famous partial skeleton of Lucy.
Work at Gona from 1992 to 1994 led to the discovery of 21 new sites containing thousands of stone artifacts and ancient animal remains, reported Seleshi Semaw of Rutgers University in New Brunswick, N.J. Numerous sharpened stone flakes, as well as the rocks they were chipped from, date to between 2.5 million and 2.6 million years ago. This is the oldest solid evidence of stone tool manufacture. The estimated age relies on an analysis of argon isotopes in a volcanic ash layer just above the finds and evidence of a previously dated reversal of Earth's magnetic field in sediment just below them.
Continuing research at Gona will address whether hominids used stone implements substantially before 2.5 million years ago, Semaw says. Some scientists argue that a global climate change around that time sparked a relatively sudden shift to stone tool use by hominids.
Excavations in 1993 and 1994 at Konso-Gardula, another group of Ethiopian sites, produced a 1.5-million-year-old A. boisei jaw, along with much of that specimen's fragmented braincase, reports Berhane Asfaw of Rutgers. Homo erectus inhabited Konso-Gardula at the same time (SN: 1/2/93, p.6).
Excitement over the new Ethiopian discoveries was tempered by the charge, leveled by Semaw and then repeated by Asfaw, that researchers from the Institute of Human Origins (IHO) in Berkeley conducted an October 1994 excavation in Gona outside their official research area and within the area secured by Semaw's team. …