Late Palaeolithic to Neolithic Transition in Cranial Affinity Based on 3D Homologous Analysis: Test “Two Layer” Model on a World-Wide Canvas

MATSUMURA Hirofumi

The transition from the Late Palaeolithic to the Neolithic period witnessed significant changes in human cranial morphology, attributed to microevolution, environmental adaptation, population admixture, and replacement, concomitant with the shift to agriculture. This 3D homologous analysis of 612 crania from 175 archaeological sites revealed that Palaeolithic hunter-gatherers in East Asia and Europe shared close cranial affinity, with features resembling Africans and Papuans. PCA demonstrated that during this transition, Northeast Asians developed enhanced masticatory bones, whereas Europeans and West Asians exhibited masticatory reduction. Comparing East Asia and Europe, cranial affinities suggest Neolithic agriculture-driven population replacement or admixture with pre-existing hunter-gatherers occurred in East Asia, as described in the Two Layer model from my previous cranial and dental studies, and reconfirmed here. In Europe, the transition was similarly drastic in the north, but southern Europe shows masticatory reduction occurring already in the Palaeolithic, challenging the simple delineation narrative based on agricultural migration and replacement model. This discontinuity likely reflects geographic scale: East Asia's large mountains and deserts hindered north-south gene flow, whereas Europe's Alps posed less of a barrier. This study explores the dispersals of Neolithic farmers and their impacts on prior populations of hunter-gatherers, on a world-wide canvas, following up Peter Bellwood’s agriculture and language dispersal scenario, using 3D cranial datasets.