Sexual Dimorphism in the Pelvic Girdle of Australian Flying Foxes

Abstract

Sexual dimorphism was observed in the pelvic girdle of all individuals and age classes of Pteropus alecto, P. poliocephalus and P. scapulatus. In females the pelvic girdle is open (V-shaped) whereas it is closed (O-shaped) in males. This striking dimorphism enabled the sex of any individual, including skeletal material alone, to be determined with 100% accuracy. In females the interpubic distance (i.e. the distance between the two pubic bones) is correlated with forearm length. The first comparative photographs of the dimorphic pelvis are presented and the usefulness of this new diagnostic character explored.