Research on Spider Monkeys

Photopigments and colour vision in New World monkeys from the family Atelidae
Gerald H. Jacobs and Jess F. Deegan II
Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara, CA 93106, USA
Department of Psychology, California State University, Bakersfield, CA 93311, USA
Most NewWorld monkeys have an X-chromosome opsin gene polymorphism that produces a variety of different colour vision phenotypes. Howler monkeys (Alouatta), one of the four genera in the family Atelidae, lack this polymorphism. Instead, they have acquired uniform trichromatic colour vision similar to that of Old World monkeys, apes and people through opsin gene duplication. In order to determine whether closely related monkeys share this arrangement, spectral sensitivity functions that allow inferences about cone pigments were measured for 56 monkeys from two other Atelid genera, spider monkeys (Ateles) and woolly monkeys (Lagothrix). Unlike howler monkeys, both spider and woolly monkeys are polymorphic for their middle- and long-wavelength cone photopigments. However, they also di¡er from other polymorphic New World monkeys in having two rather than three possible types of middle- and long-wavelength cone pigments. This feature directly influences the relative numbers of dichromatic and trichromatic monkeys.
Keywords: NewWorld monkeys; colour vision; photopigment polymorphism; opsin evolution
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