Morphological variation in the frontal bone and cranial base of Vipera aspis was studied using geometric morphometrics. Significant differences in shape were found among samples from subspecies present in Italy (V. a. aspis, V. a. francisciredi, V. a. hugyi). Sexual dimorphism was negligible as well as allometry and size differences. The most divergent subspecies was V. a. aspis, possibly in relation to its recent history of geographic isolation in a glacial refugium. Shape clusters were in good agreement with clusters from studies of external morphology and completely congruent with results from molecular studies of mtDNA
