Red-backed salamander

A not so red-backed red-backed salamander. This is a rare color morph with a white stripe instead of a red one. This is the second one that I have found. The stripe is a very pretty silvery-white. The first picture is in situ, exactly as I found her when I flipped the log she was under. The colors in amphibian skin are produced by layers of different chromatophores (color-producing cells) underneath the outer layer of skin. The first layer are xanthophores, which range in hue from yellow to red. Underneath are iridophores, which are reflective (think iridescent). Then there are melanophores, which produce dark colors (black and brown) and lie beneath and in between the xanthophores and iridophores. So if you think about the typical red-backed, the base color is black (melanophores) flecked with white (iridophores) and the stripe is red (xanthophores). In the white-striped morph, the xanthophores appear to either be lacking or "turned off" leaving only the iridophores to produce a reflective silvery-white stripe. Unfortunately, the cell morphology of this particular variation hasn't been studied, but it seems like it would be an interesting project to investigate.