Ultrastructural and biochemical analysis of epidermal xanthophores and dermal chromatophores of the teleost Sparus aurata

We have studied the pigmentary system of the teleost Sparus aurata skin by electron microscopy and chromatographic analysis. Under electron microscopy , we found the dermis to contain the three major types of recognized chroma tophores: melanophores, xanthophores and iridophores. Melanophores were mor e abundant in the dorsal region, whereas the iridophores were more abundant in the Ventral region. The most important discovery was that of epidermal xanthophores. Epidermal xanthophores were the only chromatophores in the ep idermis, something only found in S. aurata and in a teleost species living in the Antartic sea. In contrast, the biochemical analysis did not establis h any special characteristics: we found pteridine and flavin pigments locat ed mostly in the pigmented dorsal region. Riboflavin and pterin were two of the most abundant coloured pigment types, but other colourless pigments su ch as xanthopterin and isoxanthopterin were also detected.