Geometric morphometrics and the population diversity of Late Glacial horses in Western Europe (Equus caballus arcelini): phylogeographic and anthropological implications

In order to test the possibility of large migrations of wild horses between the North and the South of Western Europe during the Late Glacial, we addressed the population diversity in this area, especially during the Bölling/Alleröd periods. We based this appreciation upon the detailed morphology of the distal part of the metapodials. Landmark approaches were applied to archaeological and palaeontological samples from three distinct areas: Switzerland Plateau, Paris Basin, and Charente (France). Little differences of isometric size characterized the three regional samples. Multivariate analyses of shape (principal component analysis, discriminant, canonical variates and neural network analyses) revealed similar sets of complex shape features on both metacarpals and metatarsals. In addition, regional groups appeared clearly differentiated by well defined shape patterns, the functional implications of which remain to be established. These results evidence the existence of a regional structuration of populations (particularly clear on the CVA of both metacarpals and metatarsals) suggesting the absence of long distance migrations. Finally, it appears that the distinction between size and shape systematically operated by geometric morphometrics can provide better insights into the study of the mobility of ancient populations. Geometric morphometrics approaches such as 3D Procrustes superimpositions, appear therefore to be of great interest for archaeological purposes.