HOOD, C.S.*; ASKAR, M.: Sexual dimorphism in cranial size and shape: Miopithecus talapoin (Primates, Cercopithecidae)

Sexual dimorphism in cranial and canine size and shape was investigated in the Old World cercopithecine, Miopithecus talapoin. A sample of 31 museum specimens (23 females, 8 males) originally collected from the field in nearby locations in Rio Muni, West Africa and housed in the Tulane Museum of Natural History was used to investigate variation in cranial size and shape. It is well known that many primate species exhibit size sexual dimorphism (SSD). A large number of factors have been implicated in the origin and maintenance of SSD in primates, including sexual selection, social structure, functional morphology and ecology. Nine 2-dimensional cranial landmarks were collected using a video-based system and were imported into geometric morphometric software to describe and analyze size and shape dimorphism. Significant size (centroid size) and shape (partial warp scores) sexual dimorphism was found among these specimens. The ratio of male/female SSD for centroid size was 1.0377, which was statistically significant (ANOVA, F = 4.81, P < 0.05). Shape differences between the skulls of males and females reflect larger facial regions in males (longer upper jaw and palate), but larger braincases in females.