The evolution of projectile points and technical systems: A case from Northern Patagonian coast (Argentina)

Abstract

In this paper we present the results of the phylogenetic analysis of projectile points dating from the Middle-Late and final Late Holocene recovered from different sites along the coast of San Matías Gulf (Río Negro province, Argentina). In order to study the evolution of weapon systems we have used maximum parsimony phylogenetic reconstruction and tree based comparative methods. This allowed us to explore different evolutionary models addressing the technical systems used in the area.The results suggest the existence of a robust phylogenetic signal that gradually evolved into at least two technical systems. One of the most important results however, was the evidence of a certain morphological continuity. In turn this suggests that, rather than a direct replacement, there was an adaptation of propellant-type weapons towards the bow and arrow.We concluded that this pattern of metric and morphological continuity might be related to transitional forms between the different technical systems, with design types used in both systems. There would have been a degree of experimentation so as to produce performance effective projectile points, this would have occurred in a framework of trial and error in a context of low risk.