The study identifies melanopsin, an opsin in Xenopus laevis dermal melanophores, brain, and eye. Melanopsin shares homology with cephalopod opsins and has a long cytoplasmic tail with multiple phosphorylation sites, suggesting fine regulation. Melanopsin mRNA is expressed in hypothalamic sites, the iris, and retinal cells, indicating roles in vision and non-visual photoreceptive tasks such as skin pigmentation control, pupillary aperture, and circadian and photoperiodic physiology. The opsin's structure and phylogenetic analysis suggest it diverged from invertebrate opsins, with potential functions in deep brain photoreception and iridal photomechanical movement.The study identifies melanopsin, an opsin in Xenopus laevis dermal melanophores, brain, and eye. Melanopsin shares homology with cephalopod opsins and has a long cytoplasmic tail with multiple phosphorylation sites, suggesting fine regulation. Melanopsin mRNA is expressed in hypothalamic sites, the iris, and retinal cells, indicating roles in vision and non-visual photoreceptive tasks such as skin pigmentation control, pupillary aperture, and circadian and photoperiodic physiology. The opsin's structure and phylogenetic analysis suggest it diverged from invertebrate opsins, with potential functions in deep brain photoreception and iridal photomechanical movement.