Craniometrics Reveal “Two Layers” of Prehistoric Human Dispersal in Eastern Eurasia

Abstract

This cranio-morphometric study emphasizes a “two-layer model” for eastern Eurasian anatomically modern human (AMH) populations, based on large datasets of 89 population samples including fndings directly from ancient archaeological contexts. Results suggest that an initial “frst layer” of AMH had related closely to ancestral Andaman, Australian, Papuan, and Jomon groups who likely entered this region via the Southeast Asian landmass, prior to 65–50kya. A later “second layer” shared strong cranial afnities with Siberians, implying a Northeast Asian source, evidenced by 9kya in central China and then followed by expansions of descendant groups into Southeast Asia after 4kya. These two populations shared limited initial exchange, and the second layer grew at a faster rate and in greater numbers, linked with contexts of farming that may have supported increased population densities. Clear dichotomization between the two layers implies a temporally deep divergence of distinct migration routes for AMH through both southern and northern Eurasia. Show more