Visual pigment diversity in two genera of mantis shrimps implies rapid evolution (Crustacea; Stomatopoda)

1. Interspecific diversity in the visual pigments of s tomatopod crustaceans was characterized using microspectrophotometry. We examined the 10 visual pigments in main rhabdoms in retinas of 3 species of each of two genera of s tomatopod crustaceans of the superfamily Gonodactyloidea, Gonodactylus (G. oerstedii, G. aloha, and G. curacaoensis) and Odontodactylus (0. scyllarus, 0. brevirostris, and O. "havanensis"). Species were selected to provide a matched diversity of habitats. 2. In each genus, visual pigments varied in "~max in several regions of the retina, as revealed by analysis of variance. The variation within closely related species of the same genus implies that visual pigments can evolve rapidly in stomatopods. 3. In photoreceptors of the peripheral retina, which are devoted to spatial vision, visual pigment ~max decreased as the depth range of the various species increased, a typical pattern for marine animals. In contrast, visual pigment ~max in photoreceptors of retinal regions devoted to polarization vision (midband Rows 5 and 6) is not obviously correlated with the spectral environment, implying that polarization information may be confined to particular spectral ranges. Visual pigments of the tiered rows of the midband, which are committed to spectral analysis, span a larger spectral range in shallow-water than deepwater species. T. W. Cronin (1:~) Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21228, USA N. J. Marshall Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK R. L. Caldwell Department of Integrative Biology, University of California, Berkeley, CA 94720, USA K e y words Visual pigment 9 S t o m a t o p o d a 9 Visual ecology. Evolut ion" Photoreceptor 9 Retina Abbreviat ion MSP microspectrophotometry