Ultrastructure of the Dermal Chromatophores in a Lizard (Scincidae: Plestiodon latiscutatus) with Conspicuous Body and Tail Coloration

Abstract

Microscopic observation of the skin of Plestiodon lizards, which have body stripes and blue tail coloration, identified epidermal melanophores and three types of dermal chromatophores: xanthophores, iridophores, and melanophores. There was a vertical combination of these pigment cells, with xanthophores in the uppermost layer, iridophores in the intermediate layer, and melanophores in the basal layer, which varied according to the skin coloration. Skin with yellowish-white or brown coloration had an identical vertical order of xanthophores, iridophores, and melanophores, but yellowish-white skin had a thicker layer of iridophores and a thinner layer of melanophores than did brown skin. The thickness of the iridophore layer was proportional to the number of reflecting platelets within each iridophore. Skin showing green coloration also had three layers of dermal chromatophores, but the vertical order of xanthophores and iridophores was frequently reversed. Skin showing blue color had iridophores above the melanophores. In addition, the thickness of reflecting platelets in the blue tail was less than in yellowish-white or brown areas of the body. Skin with black coloration had only melanophores.

Ultrastructure of the dermal chromatophores in the Fringe-toed lizard, Acanthodactylus orientalis

“…Electron microscopic studies of the chromatophores of A. orientalis confirm the scattered combination of dermalchromatophores with the uppermost layer of xanthophores, the intermediate layer with iridophores and melanophores in the basal layer. This is in agreement with the findings of Kuriyama et al (2006) for Plestiodon latiscutatus Hallowell, 1861. However, there are some structural, functional and distributional differences in the iridophores.…”

“…In the dermal skin of reptiles four basic types of pigment cells have been recognized: xanthophores, erythrophores, iridophores, and melanophores (Cooper and Greenberg 1992, Bagnara 1998, Kuriyama et al 2006. The color intensity as well as the patterns of the skin in different reptilian species vary according to the distribution of epidermal melanocytes and dermal melanophores, lipophores (xantophores and erythrophores), and iridophores (Szabo et al 1973, Bagnara 1983, Gosner 1989, Cooper and Greenberg 1992, Macedonia et al 2000, Bagnara and Matsumoto 2006, Alibardi 2011, 2012, 2013.…”

“…The color intensity as well as the patterns of the skin in different reptilian species vary according to the distribution of epidermal melanocytes and dermal melanophores, lipophores (xantophores and erythrophores), and iridophores (Szabo et al 1973, Bagnara 1983, Gosner 1989, Cooper and Greenberg 1992, Macedonia et al 2000, Bagnara and Matsumoto 2006, Alibardi 2011, 2012, 2013. The spatial arrangement and architectural combination of these pigment cells can produce a multitude of skin colors in reptiles (Morrison 1995, Morrison et al 1996, Kuriyama et al 2006). In the dermis, xantophores and erythrophores (light-absorbing pigment cells) contain xantophils, carotenoids, and pterins and produce orange-yellow to reddish colors (Ferrer et al 1999, Steffen andMcGraw 2009).…”

Unraveling the thread of nature’s tapestry: the genetics of diversity and convergence in animal pigmentation

“…Therefore, the interactions between genes and the environment may be more complex for red ⁄ yellow color patches. The genetics of blue ⁄ green coloration also may be challenging to unravel because reflective colors are determined by the interaction between melanin layers and the number, size, and spacing of reflecting platelets in the iridophore cell layer (Kuriyama et al, 2006;Morrison et al, 1996).…”

Not just black and white: Pigment pattern development and evolution in vertebrates

“…Blue coloration in fish, amphibians and reptiles is due primarily to the presence of iridophores underlain by melanophores [58,64]. Iridophores and leucophores are both described as reflective or shiny pigment cells, with iridophores giving an iridescent shine and leucophores appearing white [10,51] or cream [65].…”