The Aterian is a Middle Stone Age (or Middle Palaeolithic) stone tool industry centered in North Africa, from Mauritania to Egypt, but also possibly found in Oman and the Thar Desert. The earliest Aterian dates to c. 150,000 years ago, at the site of Ifri n'Ammar in Morocco. However, most of the early dates cluster around the beginning of the Last Interglacial, around 150,000 to 130,000 years ago, when the environment of North Africa began to ameliorate. The Aterian disappeared around 20,000 years ago. The Aterian is primarily distinguished through the presence of tanged or pedunculated tools, and is named after the type site of Bir el Ater, south of Tébessa. Bifacially-worked, leaf-shaped tools are also a common artefact type in Aterian assemblages, and so are racloirs and Levallois flakes and cores. Items of personal adornment (pierced and ochred Nassarius shell beads) are known from at least one Aterian site, with an age of 82,000 years. The Aterian is one of the oldest examples of regional technological diversification, evidencing significant differentiation to older stone tool industries in the area, frequently described as Mousterian. The appropriateness of the term Mousterian is contested in a North African context, however. Source: Wikipedia (en)