Brassy Flecking in the Salamander Plethodon c. cinereus, and the Validity of Plethodon huldae

Abstract

IT is well known that some individuals of Plethodon c. cinereus Green have a well defined reddish dorsal stripe and dark sides and that others are uniformly dark dorsally and laterally. Also, some are variously intermediate between the striped and dark phases, and some are erythristic. References to these color variations are found in many accounts of the species, a good general description occurring in Bishop (1941). The present paper discusses a feature of the coloration of P. c. cinereus that apparently has never been recorded in the literature, but which has, nevertheless, figured to some extent in the taxonomy of other species of Plethodon. While collecting P. c. cinereus in the Genesee River gorge at Rochester, New York, in the autumn of 1953, I was struck by the fact that the dark ones were conspicuously peppered with tiny light flecks. Microscopic examination in the laboratory revealed that this flecking was due to numerous individual iridophores distributed more or less evenly over the whole dorsum, upper sides, and upper surfaces of the legs. These small chromatophores, which show an iridescent golden or brassy color, are located just external to the melanophores which produce the ground color of the above mentioned areas. The iridophores usually are quite small (0.02-0.05 mm. in diameter) and relatively widely separated; occasionally those on the tail, and less often those on the head or lower back, are larger (0.1 mm.) and so close as to touch one another, giving the appearance of a reticulum. In an extreme instance of the latter