Systemic stress in hunter-gatherers from the Central Pampas Dunefields (Argentina): evaluating linear enamel hypoplasia during the Holocene

Abstract

This research aims to evaluate whether the socio-environmental changes observed in the Central Pampas Dunefields (Argentina) throughout the Holocene (ca. 11,000–350 cal year BP) caused episodes of systemic stress in hunter-gatherer populations. Linear enamel hypoplasia was analyzed macroscopically with a 40×magnifying glass and oblique light in 337 teeth from 26 adult individuals recovered from 11 archaeological sites. Data were analyzed following three levels of observation: individual, tooth, and number of dental enamel lines. 42.3% of the individuals presented linear enamel hypoplasia. The lines affected males and females similarly. No statistically significant differences were observed between the three Holocene periods. The age of growth-disruption events occurred between 2 and 6.05 years, and stress episodes are registered at earlier ages in the Late Holocene than in the other periods. The causes could be related to metabolic stress associated with weaning, postweaning, variations in the availability of natural resources over time, development of infectious, and parasitic diseases during changes in social organization strategies and gastrointestinal diseases caused by non-potable water intake. At the regionallevel, Pampas shows moderate to high values of linear enamel hypoplasia, suggesting the exposure of hunter-gatherer groups to recurrent episodes of stress during the early stages of postnatal life.