Diversity in Primate External Eye Morphology: Previously Undescribed Traits and Their Potential Adaptive Value

Comparative examinations of external eye morphology in primates initially focused on communicative functions of the eye. Subsequent work has failed to find consistent associations between specific eye morphologies and communicative functions. In this article, we review the field of primate external eye morphology and inspect publicly available and unpublished photographs. We identify and describe five commonly occurring traits that have not received attention so far. We cross-examined the clinical and psychological literature to propose potential adaptive functions. These potential adaptive functions include communicative functions, but also photoregulatory functions and photoprotective functions.

Automated summary

Comparative examinations of external eye morphology in primates initially focused on communicative functions of the eye, but subsequent work did not find consistent associations. By reviewing publicly available and unpublished photographs, five commonly occurring traits were identified. The proposed potential adaptive functions include communicative, photoregulatory, and photoprotective functions.