Mobility and subsistence economy: a diachronic comparison between two groups settled in the same geographical area...

The purpose of this article is to investigate temporal shifts in skeletal robusticity to infer behavioral changes in two populations (Neolithic, NEOL and Medieval, MED) settled in the same geographic area but involved in different subsistence economies (pastoralism and coastal resources exploitation). This comparison allows us to test the hypothesis that occupational stress and mobility in the same environment produce predictable changes in the robusticity of both upper and lower limbs. Results show a lower degree of humeral robusticity and a similar degree of humeral asymmetry in the two sexes in the MED population. These results are consistent with the relatively less stressful subsistence economy documented in the MED population relative to that of the NEOL. Lower limb results suggest that femoral robusticity does not correlate directly with the level of logistical mobility, but is instead due to the summation of several diverse factors that place biomechanical loads on the hindlimb, particularly unevenness of the terrain. However, female femoral gracility seems to indicate that below a certain "threshold" of mobility, i.e., movement over the natural terrain, terrain conformation is no longer the main contributing factor to femoral robusticity. The femoral shape index I(x)/I(y) declines through time, particularly in males. This agrees with the expected mobility of the samples based on archaeological and historical data, providing further evidence on the reliability of this index in inferring terrestrial mobility.