Monday, June 11, 2012

[Mammalogy • 2012] Adaptive evolution of facial colour patterns in Neotropical primates

Faces of adult male primates from Central and South America. Warmer colors indicate higher complexity in facial color patterns. Species shown are: (1) Cacajao calvus, (2) Callicebus hoffmansi, (3) Ateles belzebuth, (4) Alouatta caraya, (5) Aotus trivirgatus, (6) Cebus nigritus, (7) Saimiri boliviensis, (8) Leontopithecus rosalia, (9) Callithrix kuhli, (10) Saguinus martinsi, and (11) Saguinus imperator
Credit: Stephen Nash

The rich diversity of primate faces has interested naturalists for over a century. Researchers have long proposed that social behaviours have shaped the evolution of primate facial diversity. However, the primate face constitutes a unique structure where the diverse and potentially competing functions of communication, ecology and physiology intersect, and the major determinants of facial diversity remain poorly understood. Here, we provide the first evidence for an adaptive role of facial colour patterns and pigmentation within Neotropical primates. Consistent with the hypothesis that facial patterns function in communication and species recognition, we find that species living in smaller groups and in sympatry with a higher number of congener species have evolved more complex patterns of facial colour. 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 facial regions. Our results demonstrate the interaction of behavioural and ecological factors in shaping one of the most outstanding facial diversities of any mammalian lineage.

Evolution Is Written All Over Your Face
ScienceDaily (Jan. 11, 2012) — Why are the faces of primates so dramatically different from one another? 
UCLA biologists working as "evolutionary detectives" studied the faces of 129 adult male primates from Central and South America, and they offer some answers in research published Jan. 11, in the early online edition of the journal Proceedings of the Royal Society B. The faces they studied evolved over at least 24 million years, they report.
University of California - Los Angeles (2012, January 11). Evolution is written all over your face. ScienceDaily. Retrieved June 11, 2012, from­ /releases/2012/01/120111223744.htm

ScienceShot: Why So Many Monkey Faces? : 

Sharlene E. Santana, Jessica Lynch Alfaro, and Michael E. Alfaro. 2012. Adaptive evolution of facial colour patterns in Neotropical primates. Proc. R. Soc. B, 279(1736): 2204-2211. DOI:  10.1098/rspb.2011.2326