Determination of age and sex on dental pieces of Lama guanicoe: A methodological approach

Abstract

Archaeozoological studies in central Tierra del Fuego are limited by the possibilities of bone conservation. This region is characterized by the development of the sub-Antarctic forest, where survival of organic material is very low, due to factors such as the acidity produced by leaves decomposition, humidity, roots action, ground freezing, etc. In order to study the archaeofauna and to discuss models of resource utilization, selection and management by past hunting-gatherer societies, it is essential to have data regarding sex and age of death of individuals. Therefore, we decided to undertake an intensive study of one type of archaeozoological remains: dental pieces of guanaco (Lama guanicoe), the main animal resource exploited by the Selk´nam and pre-Selk´nam societies. Because of their chemical and physical properties, especially their hardness (due to the inorganic hydroxiapatite matrix), teeth are expected to survive the acidic conditions of forest soils. In order to determine age and to infer seasonality from teeth samples, we use cementocronology, a histological observation technique used to count incremental lines by means of the analysis of cross sections of incisors and canines. As for sex determination, we use the amplification of the PCR, method designed to maximize the recovery of DNA in ancient samples, since it has been shown that the genetic material is better preserved in hard tissues such as bone or tooth. In this paper we present some preliminary results from the experimental stage, where present day samples of Lama guanicoe are used to adjust the different variables involved in the application of these techniques, previous to the analysis of archaeological samples from different environments of the Island. This paper is intended to show how techniques that are widely developed in different areas of biology, from population ecology to molecular biology, could contribute to solve problems of archaeological contexts.