Lithic Miniaturization Provides a Signature of an MIS4-3 Southern Dispersal of Homo sapiens

Fossil and artefactual evidence shows Homo sapiens in Eurasia well before 75 ka. However, genetic evidence suggests all extant non-African populations derive almost all of their ancestry from a dispersal that only diverged in the last 60-50 ka. In northern Eurasia, the Upper Paleolithic with its laminar blade knapping provides an archeological signature of this dispersal, but no equivalent is yet established for southern Asia, Wallacea, and Sahul. This paper suggests that lithic miniaturization may provide such a signature as it appears across these southern regions from around 50 ka. It can be traced back to the southwestern edge of Asia at 55 ka, and then coastal east Africa at 68 ka. In both these cases it is also associated with laminar blade technology. Lithic miniaturization is implicated in behaviors including bow-and-arrow hunting, compound tools, hair-shaving, and scarification. The ecological and social implications of these behaviors may have given later Homo sapiens a competitive advantage over both other hominins and earlier dispersals of our own species.