Lithic technology from level 22 at Nasera (Tanzania): The Kisele industry revisited

• The Nasera rockshelter is a key Stone Age site in northern Tanzania, with stratigraphy spanning from the Middle Stone Age (MSA) to the Pastoral Neolithic. • Level 22 at Nasera reveals an MSA industry characterized by discoid knapping methods, dominated by sidescrapers and bifacial and unifacial points. • The raw materials used, such as quartz and chert, are locally sourced, while the presence of obsidian suggests long-distance contact. • The study of level 22 contributes to challenges the monolithic view of the MSA, revealing greater technological complexity and human interactions. This study presents a techno-typological analysis of level 22 at the site of Nasera (northern Tanzania), shedding new light on the Kisele industry (Middle Stone Age) in the region. The lithic assemblage is predominantly characterized by discoid methods and the use of sidescrapers and points, both bifacial and unifacial. The raw materials used are primarily local in origin, including quartz and chert from Olduvai. However, the presence of a small number of obsidian pieces originating from Lake Naivasha basin suggests long-distance contact between MSA groups. In addition to the discoid methods, other operational schemes, such as the Levallois or the single platform, have been identified in smaller numbers, with higher-quality materials such as chert used in the Levallois. This indicates a greater variability in the number of production methods used than that previously identified for the Kisele industry. Comparisons with other regional industries, such as the older Sanzako, or contemporaneous ones like VCS and DGS at Olduvai or Loiyangalani in the Serengeti, show techno-typological differences that present a scenario of greater technological complexity and diversity than previously known for northern Tanzania.