Homo ergaster KNM-ER 3733 Skull

Homo ergaster skull. KNM-ER 3733. Confirmed the co-existence of Homo and Australopithecines in Eastern Africa. Considered a female. Homo ergaster is an extinct hominin species (or subspecies, according to some authorities) which lived throughout eastern and southern Africa between 1.9 to 1.4 million years ago with the advent of the lower Pleistocene and the cooling of the global climate. H. ergaster is sometimes categorized as a subspecies of Homo erectus. H. ergaster may be distinguished from H. erectus by its thinner skull bones and lack of an obvious sulcus. Derived features include reduced sexual dimorphism; a smaller, more orthognathic (straight jawed) face; a smaller dental arcade; and a larger (700 and 850 cm³) cranial capacity. It is estimated that H. ergaster stood at 1.9 metres (6.2 ft) tall. Remains have been found in Tanzania, Ethiopia, Kenya, and South Africa.