Suspected limited mobility of a Middle Pleistocene woman from Southern Italy: Strontium isotopes of a human deciduous tooth

Abstract

We present the Sr isotopic composition of enamel of the most ancient deciduous tooth ever discovered in Italy to assess human mobility in Middle Pleistocene. Reconstructing ancient mobility is crucial for understanding human strategy at exploiting temporally and spatially patchy resources, with most studies focusing on indirect evidences, ultimately affecting our interpretation on hominin territoriality and energetic costs invested by hominin groups. Here, we use the high spatial resolution and micro-destructivity options offered by the Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry technique, to determine the 87Sr/ 86Sr intra-tooth variability of a human deciduous incisor from the Middle Pleistocene layers of the Isernia La Pineta site (Italy). We compared these data with the Sr isotopic signature of local micro-mammals, the broadest home-range of the macro-mammals and with modern plant samples. Our study reveals that while macro-mammals have possibly migrated through the landscape for up to 50 km, the pregnant woman from Isernia was probably local, given that the isotopic ratio of the enamel falls within the local range and is comparable with the signature of the local plants in a radius of 10 km. This is the first case study of Sr isotopic composition determination in such ancient deciduous tooth.