This work is focused in the study of Patagonian lithic projectile points shape variation from a phylogenetic perspective pursuing three main aims: first, generate a model of projectile point shape diversification and morphospace evolution; second, estimate shape variation through time, and finally, assess the robustness of previous results using the same methods but in a larger sample with better spatial coverage. A previous work using geometric morphometric and cladistic methods suggested a pattern of general morphological diversification across Patagonia related, at least in part, to the spatial distance between cases, distinguishing two main clades in northern (43-45° S) and southern (50-52° S) Patagonia. In the present work to study this pattern in a more detailed level, a sample of ca. 1200 projectile points was used to obtain statistically different morphological classes performing unsupervised K-means searching. Shape characters were used to describe the different taxonomic units and to perform the phylogenetic analysis (through the Neighbor Joining and Maximun Parsimony methods) using as an ancestor the earliest point type known to the region (Fishtail point). The new results suggest that projectile points with longer and narrow blades and smaller stems evolved later in Patagonia and occupy a different sector of morphospace that could be related to the emergence of different technical systems, like the bow and arrow. However, these results do not support the previous ones of a projectile point diversification pattern mediated by spatial distance, maybe due to the reduction of contrast between the extreme north and south of Patagonia by the larger spatial coverage used in the present analysis.

中文翻译：

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巴塔哥尼亚茎点的系统发育分析：形状变化和形态空间演化

这项工作的重点是从系统发育的角度研究巴塔哥尼亚岩质弹丸点的形状变化，其目的主要是三个方面：首先，建立弹丸点形状多样化和形态空间演化的模型；第二，估计随时间变化的形状，最后，使用相同的方法，但在具有更好空间覆盖的较大样本中，评估先前结果的鲁棒性。先前使用几何形态计量学和分类法进行的研究表明，巴塔哥尼亚地区的总体形态多样化模式至少部分与病例之间的空间距离有关，从而区分了北部（43-45°S）和南部（50- 52°S）巴塔哥尼亚。在目前的工作中，我们将更详细地研究这种模式。使用1200个射弹点来获得执行无监督K均值搜索的统计上不同的形态学类别。形状特征用于描述不同的分类单位，并使用该区域已知的最早点类型（鱼尾点）作为祖先来执行系统发育分析（通过Neighbor Joining和Maximun Parsimony方法）。新的结果表明，长而窄的叶片和较小的茎的弹丸点在巴塔哥尼亚后来演化，并占据了不同的形态空间部分，这可能与不同技术系统的出现有关，例如弓箭。但是，这些结果不支持以前的以空间距离为中介的弹点多样化模式，