Insights on patterns of developmental disturbances from the analysis of linear enamel hypoplasia in a Neolithic sample from Liguria (northwestern Italy).

ABSTRACT

OBJECTIVE: To assess developmental disturbances through the analysis of linear enamel hypoplasia (LEH) frequency and to infer environmental stress and life history within Neolithic communities from Liguria (Italy). MATERIALS 43 unworn/minimally worn permanent anterior teeth of 13 individuals recovered from nearby caves and dated to c. 4800-4400 cal. BCE. METHODS: LEH defects were identified with high-resolution macrophotos of dental replicas, age at LEH was calculated via perikymata counts. LEH defects matched between two or more teeth were considered as systemic disturbances. LEH frequency by age classes was analyzed via GLZ and Friedman ANOVA. RESULTS: Number of matched defects per individual range between 2-12. The mean LEH per individual was highest in the 2.5-2.99 age category, with a significant increase relative to earlier growth stages, followed by a decline. CONCLUSION: LEH may reflect life-history in the local ecology of Neolithic Liguria, where several individuals with osteoarticular tuberculosis have been recorded. Disease burden may have triggered developmental disturbances around the time of weaning. Age at first defect was negatively correlated with age at death and positively with the total number of defects, suggesting that early stress may have affected survivorship. SIGNIFICANCE: The study contributes to the reconstruction of ecological pressures among Neolithic people of Liguria, and informs on environmental challenges during the Neolithic adaptive expansion. LIMITATIONS: The visual examination of macrophotos is prone to observer error; mid-crown tends to display more visible LEH due to tooth architecture. SUGGESTIONS FOR FURTHER RESEARCH Apply different quantitative methods to examine severity and duration of disturbances.