Melanophore distribution within the integumentary tissues of two teleost species, Pseudopleuronectes americanus and Gasterosteus aculeatus form leiurus

Abstract

In winter flounder, dermal melanophores are prominent chromatic components in the skin of the entire upper surface, and their arrangement is affected by imbrication of the ctenoid scales. Epidermal melanophores are also prominent over most of the body upper skin, scale imbrication having relatively little effect on their arrangement. Epidermal melanophores occur only sparsely on the fins and head skin, and are virtually absent from white spots of flounder disruptive patterns. In stickleback, epidermal melanophores were not observed. Melanophores with thin processes form a superficial dermal layer in the dorsal skin of the head and body of stickleback, and along the fin dermal supports. Melanophores with broad, wedge-like, processes form an extensive and continuous deep dermal layer in most of the body skin, which lacks scales, and on the operculum. Imbrication of the small number of lateral bony plates behind the operculum in leiurus sticklebacks does not greatly affect the melanophore arrangement. The skin structure of both species shows sexual dimorphism, but the respective melanophore layers are strongly developed in each sex.