Contents lists available at ScienceDirect Journal of Archaeological Science: Reports journal homepage: www.elsevier.com/locate/jasrep Life history or stylistic variation? A geometric morphometric method for evaluation of Fishtail point variability Rafael Suárez a, ⁎ , Marcelo Cardillo b a Departamento de Arqueología, FHCE, Universidad de la República, Av. Uruguay 1695, Montevideo, Uruguay b Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Multidisciplinario de Historia y Ciencias Humanas, Saavedra 15. 5to piso, Buenos Aires, Argentina ARTICLE INFO Keywords: Fishtail points Late Pleistocene Reduction index Geometric morphometrics Multivariate regression Uruguay ABSTRACT Fishtail points are considered an indicator of the presence for one of the earliest and most successful human adaptations during the late Pleistocene in South America (~12,900–12,200 cal BP). Although these points dis- play a wide range of variability both in size and shape, previous studies are mainly technological and descriptive observations. No efforts have been made to propose qualitative and quantitative indexes in order to understand how the rejuvenation/resharpening process may have affected the observed variability. In this paper, we explore different analytical methods to understand the rejuvenation process, explain the morphological variability of the Fishtail points and evaluate them from the perspectives of geometric morphometrics and multivariate statistics. This analysis allows us to generate new fresh interpretations and ideas about the rejuvenation of points. The combination of 2d geometric morphometrics, linear measurements, and multivariate regression, supports the hypothesis that the continuum of shape variation is explained by the long life history trajectories of the Fishtail points. 1. Introduction Fishtail (or Fell 1) stone points were made by the human groups that spread across large regions of Central and South America during the late Pleistocene, ca. 12,900–12,200 cal BP (Fig. 1)(Waters et al., 2015; Suárez, 2019b). These artifacts are recorded from Central America (Bird and Cooke, 1978; Acosta-Ochoa et al., 2019) to Tierra del Fuego (Borrero, 1999; Massone, 2004) on a north-south axis. On a west-east axis, there are records on both sides of the Andes, on the Pacific coast (north and central Chile) (Núñez et al., 1994; Méndez, 2015), and in the grasslands that extend to the Atlantic Ocean (Suárez, 2000, 2011a, 2017; Flegenheimer et al., 2013). Fishtail points are concentrated in at least four regions in the Southern Cone (between 25° to 55° lat. South), the plains of Uruguay, Pampas (Argentina), central Patagonian plateau (Argentina) and southern Chile. At 13 sites in the Southern Cone, Fishtail points have been re- covered from stratified contexts and dated by radiocarbon (Weitzel et al., 2018). In Uruguay, Fishtail points were found in stratigraphic context at the Tigre and Urupez sites (Fig. 2). The median probability of 11 radiocarbon dates come from theses indicate an age of ~12,800–12,200 cal BP (Table 1) for the Fishtail occupations of this region (Suárez, 2019b). The first records of Fishtail points in the Pampas and Uruguay were published at the end of the 19th century (Figueira, 1892; Ameghino, 1918 [1880]). After Fishtail points were found in association with Pleistocene fauna in Fell's Cave, (Bird, 1938; Bird, 1970), they became iconic markers of one of the basal cultural strata of South American prehistory. Several different scenarios have been proposed to explain the wide distribution of this technology in the Southern Cone and elsewhere in South America. The traditional idea suggests that the Fishtail groups originated as a branch of the Clovis culture of North America and moved very rapidly southward, leaving their characteristic points as evidence of their passage through different regions (Buchanan and Hamilton, 2009; Fiedel, 2000, 2005). Other authors suggest that Clovis and Fishtail have an independent origin (Borrero, 1983; Politis, 1991). Recently, from technological evidence it was proposed that both Clovis and Fishtail Peoples could have evolved in different ways in North and South America from a common ancestor (Suárez, 2014; Suárez, 2015). Both cultures/technologies are practically synchronous with little chronological difference in their first appearance (ca. 13,000 cal BP) and represent human adaptations to diverse terminal Pleistocene en- vironments across North and South America (Waters, 2019). The Clovis and Fishtail technology share the fluting of the point base, and the data obtained in Uruguay also suggest the presence of overshot flaking and a https://doi.org/10.1016/j.jasrep.2019.101997 Received 16 May 2019; Received in revised form 13 August 2019; Accepted 18 August 2019 ⁎ Corresponding author. E-mail address: rsuarez@fhuce.edu.uy (R. Suárez). Journal of Archaeological Science: Reports 27 (2019) 101997 2352-409X/ © 2019 Elsevier Ltd. All rights reserved. T