Cranial variability of the Serbian red fox

We used geometric morphometric techniques to examine variability in Serbian red fox (Vulpes vulpes) crania. Male crania are about 5% larger than female ones and sexual size dimorphism (SSD) was significant. Also, significant cranial shape differences were found between the sexes. Males are characterized by reduced basicranial, but broader rostral and zygomatic regions. Although a slight and significant allometric effect was detected and larger specimens are smaller in the region of basicranium, cranial sexual shape dimorphism (SShD) pattern is not influenced by SSD. As small to moderate SSD in canid species is a general characteristics of the family, additional studies are needed to determine whether basicranial reduction in males, i.e. its enlargement in females, could be an important feature in characterizing cranial SShD patterns in other Canidae members. While uniform considering size, the shape of Serbian red fox crania varies geographically, as well as depending on proportion of agricultural habitats. In comparison to those from central and eastern Serbia, specimens from the northern Serbian region Vojvodina (with higher proportions of agricultural areas) have more robust crania with shorter snouts and maxillae, larger palatine bones accompanied with anteriorly moved posterior edges of the canine alveolus and laterally expanded zygomatic arches. Encompassing mostly facial and temporal cranial regions these shape changes are probably related to diet differences, although genetic diversification cannot be excluded as a possible contributing factor.