Dimorfismo sexual em crânios de macacos parauaçus, cuxiús e uacaris (Pitheciidae, Platyrrhini)

Abstract

Within all neotropical primates, pitheciines stand out for their elusiveness. The sampling of sakis, bearded-sakis and uakaris is particularly hard, because these monkeys inhabit the towering amazonian tree canopies. The external sexual dimorphism varies substantially among pitheciine species, with some being highly dimorphic, while others are barely distinguishable. This study’s principal aim is to measure and compare the sexual dimorphism in three genera: Pithecia, Chiropotes an Cacajao. For reaching this goal, 21 morphometric variables were analyzed, which are divide into 3 domains: facial, neural and neutral. These variables were subjected to statistic tests, both univariated and multivariated, such as hypothesis testing, correlation analysis, MANOVA, PCA and LDA. Pithecia displayed low dimorphism values, as most variables didn’t differ significantly between the sexes. However, Chiropotes and Cacajao revealed a moderate degree of sexual dimorphism, as most of the variables generated a relevant morphometric isolation between males and females. The facial domain consistenly shown a higher dimorphic level than the neural and neutral counterparts.