Northern Laos as a Diversity Hotspot During the Chibanian: New Evidence from Tam Sot and the Question of Survival

Fabrice Demeter

Northern Laos is rapidly emerging as a key region for understanding hominin diversity during the Chibanian (i.e., Middle Pleistocene). Within a vast karst landscape, three distinct hominin lineages are now documented: early Homo sapiens at Tam Pà Ling, Denisovans (Homo longi) at Cobra Cave, and a newly discovered human tooth from Tam Sot, currently under publication and attributed to Homo erectus. This concentration of fossils suggests that the Annamite chain of Northern Laos was not peripheral, but central to Middle Pleistocene human diversity in mainland Southeast Asia. Multiple hominin lineages appear to have coexisted within the same regional landscape during periods of climatic instability and environmental restructuring. Yet only Homo sapiens persisted from the end of the Late Pleistocene onward. By situating the Tam Sot specimen within its faunal and stratigraphic context, and integrating ongoing isotopic and proteomic analyses, sedaDNA from the sediment and breccia we explore whether differences in ecological breadth, mobility, and tolerance to environmental variability may help explain long-term persistence. The Tam Sot tooth is not just a new fossil discovery; it helps position northern Laos and mainland Southeast Asia as central to explaining why human diversity in that region did not lead to long-term survival.