Investigation of the osteometry of the skull of the one-humped camels. Part II: sex dimorphism and geographical variations in adults.

Sexual dimorphism in the skull of different species has been of importance in archaeological, forensic and anatomical studies; also, a variation in phenotypic and genetic traits across geographic space is a recurring phenomenon in biological species. This study investigated 10 adult camels from each of three geographical locations in northern Nigeria, for sex- and location-based variations in the skulls. In one location, male skulls had greater absolute osteometric values but there were no significance differences in relative proportions between sexes. Moreover, all index values (skull, cranial and facial) indicate no sexual dimorphism in all locations. There were some variations in the osteometry of the frontal region, and neurocranial volume between the locations. In addition it was observed that the skull index of Nigerian camels was similar to the Malha type documented in literature but wide variations exist in many other craniometric dimensions of the skull. This suggests a definite difference in phenotype and probable origin.