Evolution of facial color pattern complexity in lemurs

Hanitriniaina Rakotonirina,Peter M Kappeler,Claudia Fichtel

doi:10.1038/s41598-017-15393-7

Abstract

Interspecific variation in facial color patterns across New and Old World primates has been linked to species recognition and group size. Because group size has opposite effects on interspecific variation in facial color patterns in these two radiations, a study of the third large primate radiation may shed light on convergences and divergences in this context. We therefore compiled published social and ecological data and analyzed facial photographs of 65 lemur species to categorize variation in hair length, hair and skin coloration as well as color brightness. Phylogenetically controlled analyses revealed that group size and the number of sympatric species did not influence the evolution of facial color complexity in lemurs. Climatic factors, however, influenced facial color complexity, pigmentation and hair length in a few facial regions. Hair length in two facial regions was also correlated with group size and may facilitate individual recognition. Since phylogenetic signals were moderate to high for most models, genetic drift may have also played a role in the evolution of facial color patterns of lemurs. In conclusion, social factors seem to have played only a subordinate role in the evolution of facial color complexity in lemurs, and, more generally, group size appears to have no systematic functional effect on facial color complexity across all primates.

Highlights

Interspecific variation in facial color patterns across New and Old World primates has been linked to species recognition and group size
In Neotropical primates, interspecific variation in facial color pattern was greater in species living in smaller groups and explained by the possibility of greater reliance on facial expression in species living in larger groups[8]
Generalized Least Square (PGLS) regressions to test for evolutionary relationships among diversity in facial color patterns and social as well as ecological variables

Summary

Introduction

Interspecific variation in facial color patterns across New and Old World primates has been linked to species recognition and group size. Variation in facial hair length and color has been linked to ecological factors Both New and Old World primates with longer facial hair occur more often in cooler areas, and those exhibiting darker facial www.nature.com/scientificreports/. With currently more than 100 recognized species, lemurs are taxonomically diverse, they occupy a range of different forest habitats from dry to humid forests[37,38], and they exhibit all major forms of social organization found among anthropoid primates[39,40] They exhibit variation in activity patterns, including nocturnal, cathemeral and diurnal species[41]. From the perception side, variation in color patterns should be meaningful for lemurs, this assumption remains to be demonstrated experimentally

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