The Aterian is a Middle Stone Age (or Middle Palaeolithic) stone tool industry centered in North Africa, but also possibly found in Oman and the Thar Desert. The earliest Aterian dates to c. 145,000 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.
The technological character of the Aterian has been debated for almost a century, but has until recently eluded definition. The problems defining the industry have related to its research history and the fact that a number of similarities have been observed between the Aterian and other North African stone tool industries of the same date. Levallois reduction is widespread across the whole of North Africa throughout the Middle Stone Age, and scrapers and denticulates are ubiquitous. Bifacial foliates moreover represent a huge taxonomic category and the form and dimension of such foliates associated with tanged tools is extremely varied. There is also a significant variation of tanged tools themselves, with various forms representing both different tool types (e.g., knives, scrapers, points) and the degree tool resharpening.
More recently, a large-scale study of North African stone tool assemblages, including Aterian assemblages, indicated that the traditional concept of stone tool industries is problematic in the North African Middle Stone Age. Although the term Aterian defines Middle Stone Age assemblages from North Africa with tanged tools, the concept of an Aterian industry obfuscates other similarities between tanged tool assemblages and other non-Aterian North African assemblages of the same date. For example, bifacial leaf points are found widely across North Africa in assemblages that lack tanged tools and Levallois flakes and cores are near ubiquitous. Instead of elaborating discrete industries, the findings of the comparative study suggest that North Africa during the Last Interglacial comprised a network of related technologies whose similarities and differences correlated with geographical distance and the palaeohydrology of a Green Sahara. Assemblages with tanged tools may therefore reflect particular activities involving the use of such tool types, and may not necessarily reflect a substantively different archaeological culture to others from the same period in North Africa. The findings are significant because they suggest that current archaeological nomenclatures do not re