site in northern Tanzania known for a 400,000-year-old human cranium and associated Stone Age tools discovered there in 1973. The skull displays traits of both Homo erectus and H. sapiens (Homo sapiens), with a brain size intermediate between the two species. Like H. erectus, it has a large browridge, another ridge along the rear of the skull, and a thick-boned braincase. However, the shape of the braincase is more similar to that of H. sapiens in having vertical sides. It resembles the Kabwe (Kabwe cranium) specimen and is tentatively classified by paleoanthropologists as the same species, H. heidelbergensis (Homo heidelbergensis), a species that was present in Africa by about 600,000 years ago and in Europe by 500,000 years ago. H. heidelbergensis represents a stage in human evolution between African H. erectus (referred to by some paleoanthropologists as H. ergaster) and later species of the genus Homo, including Neanderthals (H. neanderthalensis) as well as modern humans (H. sapiens). Tools found at the site included a hand ax, but most of the artifacts were nondescript cores, hammerstones, and flakes, probably of the Acheulean industry.