This work presents the study of the Toumboura VIII site (TMB VIII), discovered in the lower Falémé Valley in eastern Senegal during the 2023 archaeological mission. OSL dating places the site's occupation around 23 ± 2 ka, between the end of Marine Isotope Stage 3 and the beginning of Marine Isotope Stage 2 (MIS 3 and 2), a period marked by significant climatic changes. The MIS 2, an arid phase also known as the "Big Dry," corresponds to an archaeological hiatus in many regions of Africa, particularly in West Africa, as observed in the Ounjougou sequence in Mali. In the Falémé Valley, this period coincides with the transition between the Middle Stone Age (MSA) and the Later Stone Age (LSA).

The typo-technological analysis of the lithic industry from TMB VIII (703 artifacts) reveals a production primarly made on locally sourced greywacke, with secondary exploitation of quartz and chert. Three distinct chaînes opératoires were identified for greywacke, aimed at producing flakes of varying morphologies and dimensions. Quartz knapping was mainly carried out using bipolar percussion on anvil. The assemblage shows neither the typical characteristics of the MSA (no Levallois method, no bifacial points) nor those of the LSA (absence of geometric microliths).

Comparison with other sites in the lower Falémé Valley shows that TMB VIII belongs to a group of "intermediate" sites, chronologically and technologically situated between the MSA and the LSA. A broader comparison with MSA and LSA sites in West Africa highlights the diversity of technical behaviors during these periods. These industries challenge traditional definitions of African Paleolithic techno-complexes and highlight the need for further research to better understand this transition period.