Morphological diversification of stemmed projectile points of patagonia (Southernmost South America). Assessing spatial patterns by means of phylogenies and comparative methods

Abstract

The aim of this work is to model patterns of morphological variation in Middle-Late Holocene stemmed projectile points from Patagonia through comparative methods. With this purpose, we explore the potential of different analytical strategies using projectile point shapes, obtained by means of geometric morphometrics. Phylogenetic and spatial variations were used to model morphological patterns on different scales. Morphological data comes from digitized images of projectile points from different areas of Patagonia. Morphometric characters were obtained using landmark and semilandmark descriptors. Mean shape by area was computed and used in cladistic analysis to model diversification trends. Then, phylogenetic and geographical coordinates were estimated for each data set and used as predictor variables in multiple regression procedures. Results suggest that historical patterns of shape change are channeled by spatial dimension. Pattern of mobility and interaction among human populations in Patagonia in the Middle-Late Holocene are discussed in light of these results.