Intraspecific differentiation and sexual dimorphism in giant deer ( Megaloceros giganteus Blumenbach, 1799; Artiodactyla, Cervidae) skulls found in Serbia

Abstract

We conducted a study of intraspecific differentiation and sexual dimorphism in skulls of giant deer found in Serbia by employing methods of geometric morphometrics. The sample consisted of nine males (seven belonging to Megaloceros giganteus cf. ruffii and two belonging to subspecies M. giganteus cf. giganteus) and two females (both classified as M. giganteus cf. ruffii), photographed in ventral and lateral views. The statistical analyses did find significant shape differences between possible subspecies and sexes for the lateral cranium view but not for the ventral. Possible subspecies differed in the overall skull robustness. Sexual shape dimorphism consisted of transition from higher and elongated skulls in females, to more robust and dorsoventrally flattened skulls in males. The allometry was not proven to be statistically significant, but the shape changes related to size variation could be visually described. Some of the shape differences related to sexual dimorphism can be interpreted as an adaptation for bearing large antlers in males. Even with small sample size, we got statistically supported differences between possible subspecies and sexual shape dimorphism in the lateral view of the giant deer skull. In analyses that showed no statistical support, methods of geometric morphometrics still provided good visualization of shape variation.