From Aterian notch to Aterian tang. How to make a technological invention

The Aterian lithic techno-complex that characterizes the late Middle Stone Age in North Africa is well known especially for its tanged or stemmed points. Recent techno-morphological and use-wear analyses have added new data to support the identification of the tang as the hafted portion of an artifact. They have also highlighted the presence of this attribute on tools other than projectile points, in contrast with the widespread idea that the tanged point is the Aterian fossile directeur. The design of this specific device, the tang, for hafting purposes is regarded as a great technical innovation that underlines a modern behavior. Our work provides new use-wear and experimental data, aiming at discussing the cognitive preconditions of this technical innovation that could have originated from a specific functional unit: the notch. Notches are quite abundant in the Aterian techno-complex. Our systematic study of this tool category from Aterian sites of the Jebel Gharbi allowed defining the notch per se as a techno-morpho-functional unit that was "applied" to different types of blanks, including "reused blanks," which show a heavy patina on their surface. This functional unit has been used for various types of activities and can be found either alone on a blank or with multiple other units on the same blank, creating different tool morphologies. According to this interpretation, the tang could have been considered by Aterian populations as a new resulting variant of various possible combinations of notches, for defining and/or transforming the shape of a tool