Multifactorial temporo-spatial structuring of the morphological diversity of domestic pigs, sheep, and goats between Catalonia (Spain) and Languedoc (France) from the Iron Age to Antiquity

In North-western Mediterranean basin, from Southern France to North-eastern Iberia, the transition from the Iron Age to Antiquity is marked by significant political, economic, and cultural changes, as well as a major shift in the body size of livestock, particularly cattle. However, the evolution of suids and caprines during this period has been less thoroughly investigated in the area. This study aims to investigate the morphological variation of sheep, goats, and pigs from the Rhône to the Ebro rivers, from the First Iron Age to Late Antiquity (eighth century BCE to sixth century CE). To this end, 1,099 caprine and 384 suid third lower molars from 96 archaeological sites were analysed using a 2D landmark and sliding semi-landmark based geometric morphometric approach. The impact of a series of socio-economic and environmental factors on the morphometric variation was tested considering time, geography, altitude, topography and urban/rural categorisation of the sites. The results indicate that while sheep teeth increased in size and differ in shape between the Second Iron Age and the end of the Roman Empire, no variation was observed in goat teeth measurements, suggesting different selection patterns for the two species over time. For suids, no differences in teeth size were detected, but differences in shape were observed throughout the chronology, possibly reflecting zootechnical improvements. While little, or no effect of different factors was found for the teeth of suids and goats, the shape of sheep teeth exhibits clear geographical structuring, along with effects of altitude, topography and site type. Thus, changes in tooth shape and size in domestic species are not the result of a single explanatory factor, but rather reflect multifactorial influences including both environmental and anthropological factors. The importance of these influences may vary over time and between species.