Dental Microwear Evidence of Holocene Dietary Variability in the Argentinian Pampas and Paraná Delta

This study explores the subsistence strategies of Middle-to-Late Holocene human populations in the Argentinean Pampas and Paraná River Delta by analyzing dental microwear patterns.

We examined occlusal molar microwear textures of individuals from the Middle and Late Holocene recovered from 12 archaeological sites across three ecologically distinct areas: the Upper Delta of the Paraná River, Central Pampas, and the lower Colorado River Valley.

Our results reveal both expected and unexpected trends. Individuals from the resource-rich Upper Delta of the Paraná River exhibited the predicted high dietary diversity (indicated by elevated mean heterogeneity (Hasfc81) values) but also showed surprisingly high mean complexity values (Asfc)-exceeding even those from the two semi-arid areas (Central Pampas and lower Colorado River Valley), where environmental abrasives would have been expected to have resulted in greater microwear texture complexity.

Within the Paraná Delta, significant intra-site variation at Los Tres Cerros 1 suggests differential food access, possibly tied to social stratification in the Goya-Malabrigo archaeological entity. In the Central Pampas, Middle Holocene individuals from the Arroyo Seco 2 archaeological site displayed greater dietary heterogeneity than contemporaneous and Late Holocene sites, contradicting expectations of progressive diversification during this period. These findings underscore that prehistoric subsistence strategies emerged from complex interactions between ecological constraints and cultural practices, including food processing and social organization.