67.1 Friday, Jan. 6 Adaptive evolution of facial color patterns in Neotropical primates SANTANA, S.E.*; LYNCH ALFARO, J.; ALFARO, M.E.; University of California Los Angeles; University of California Los Angeles; University of California Los Angeles firstname.lastname@example.org
The rich morphological diversity of primate faces has captured the attention of naturalists for over a century. Researchers have long proposed that social behaviors have primarily shaped the intraspecific variation and interspecific diversity of primate faces, as predicted by the behavioral drive model of evolution. However, the primate face constitutes a complex structure where the potentially competing functions of communication, ecology and physiology intersect, and the major determinants of facial diversity still remain poorly understood. Here we examine the relationship among facial traits, social and ecological factors within the radiation of New World primates. Through a phylogenetic comparative approach, we provide the first evidence for an adaptive role of facial color patterns and coloration in primates. Consistent with the hypothesis that facial patterns function in communication and species recognition, we find that species living in smaller groups and in high degrees of sympatry with congeners have evolved more complex patterns of facial coloration. The evolution of facial pigmentation and hair length is linked to ecological factors, and ecogeographical rules related to UV radiation and thermoregulation are met by some but not all facial regions. Our results demonstrate the interaction between behavioral and ecological factors in shaping one of the most outstanding facial diversities of any mammalian clade.