Tracing Human Diversity in South America's Southern Cone: Linguistic, Morphometric, and Genetic Perspectives

Studying the relationship between biological and cultural diversity can lead to rich insights into human history. South America has been relatively neglected in this kind of work, even though it intriguingly exhibits unexpectedly high biological and cultural diversity. Here, we focus on a particularly understudied part of the continent, the Southern Cone, and examine linguistic, craniometric, and genetic variation across five groups: Selk'nam, Qawaskar, Mapuche, Kunza, and Qom.

We retrieved craniometric and genetic data from public databases and coded linguistic data capturing variation in sound systems and grammatical structures specifically for this study. We calculated distance matrices (Mahalanobis, Jaccard, F_ST) and compared them using partial Mantel, Procrustes analysis, and multidimensional scaling in R.

Selk'nam and Qawaskar exhibit the strongest linguistic and craniometric similarities, likely due to geographic proximity, while Mapuche and Qom are the most genetically similar, reflecting recent migrations. Consistent with global studies, we observed a statistically significant correlation between the relatively plastic cranial vault morphology and the quickly evolving linguistic variables. Genetic variability was moderately related to geography, while the weakest correlation was found between the temporal bone morphology and genetic variation.

Although this study is limited by a small sample size and requires further research validation with larger datasets, our findings highlight the importance of integrating multiple datasets to better understand the interplay between biological and cultural diversity in shaping human history. Our findings also indicate that structural linguistic data help reconstruct population history, particularly at recent and intermediate scales.