Entheseal changes among late Holocene hunter-gatherers from the southern extreme of La Plata basin (Argentina)

Abstract

Different aspects of bone morphology have been studied worldwide with the purpose of explaining their causative factors and if they are suitable for inferring activities from past societies. Among them, entheseal changes have been widely analyzed and several researchers agree on their multifactorial etiology. The main objective of this work is to understand patterns of variation in entheseal changes in a sample of adult individuals of both sexes from late Holocene complex hunter-gatherers that inhabited the southern point of the La Plata basin. For that purpose, entheseal ruggedness at fibrous and fibrocartilaginous entheses is analyzed in relation to age, sex, body size, midshaft robusticity indices (as a probable proxy of physical activity levels), and archaeological site variability, through generalized linear models. The results show that physical activity, sex and age are the most important factors in determining entheseal morphology. Generally, high levels of entheseal changes were found among males, in older and large-bodied individuals, and among robust anatomical units. However, some entheses showed an inverse pattern. This leads us to propose that social (sexual and age division of labor) as well as biological factors (hormones, genetic and degenerative changes) could have an influence on entheseal changes. No differences were found between fibrous and fibrocartilaginous entheses.