Directional and fluctuating asymmetries in domestic pig skulls

Abstract

Morphological symmetry and asymmetry of skulls of domestic pig (n=29) were studied using geometric morphometric (GM) methods on the ventral aspect. Fluctuating asymmetry (FA) was used as an indicator of environmental stress, and directional asymmetry as a biomechanical constraint. The two-dimensional coordinates of 27 landmarks were digitized and analysed using GM. Multivariate analyses showed the presence of subtle but significant FA in the entire sample, and distinctive differences were detected between age groups. On the whole, these results are indicative that environmental stress is present, but no symmetry alterations were noted. On the whole, morphometric studies should open up promising areas of research in this nearly unexplored field, to study environmental stress morphometrically in domestic ungulates.