Visual receptor pigments in the african cichlid fish,Haplochromis burtoni

Abstract

The retinal receptors of the African cichlid fish,Haplochromis burtoni, are arranged in a mosaic of square arrays which have four double cones around a central cone. Microspectrophotometric measurement of spectral absorbance reveals that the short single cones contain the blue photopigment, P455, while the larger double cones contain “red-green” pigment pairs of P562 and P523. Rods are interspersed throughout the cone array and contain rhodopsin, P500. Spectral shape, pigment absorbance and the λ_max of photo-products are characteristic of A₁ based pigments. The retinal receptors of H. burtoni appear to be well matched to important visual recognition tasks.