Cranial shape variation in ontogenetic series of domestic dogs and wolves. Groups are subdivided into juveniles and adults (all permanent teeth fully erupted into occlusion), as indicated by different shapes of data points and convex hulls. Wireframes of crania (for details see Fig. 4) represent extreme shapes on principal components (PC) 1 and 2. Ontogenetic changes are mainly along PC1, whereas PC2 indicates group/breed specific changes.