Comparative Morphology of the Skin ofNatrix tessellata(Family: Colubridae) andCerastes vipera(Family: Viperidae)

Abstract

We studied beneficial difference of the skin of two snakes. Two snakes were chosen from two different habitats and two families: Colubridae (Natrix tessellata) and Viperidae (Cerastes vipera). The investigations were performed by light and electron microscopy. Histologically, the skin of the studied species show pronounced modifications that correlated with functional demands. The scales in Natrix tessellata overlapped slightly, while in Cerastes vipera they were highly overlapped. SEM shows that scales of Natrix tessellata had bidentate tips while the scales of Cerastes vipera were keeled. Histochemically, in both studied species, melanocytes and collagenous fibres were distributed throughout the dermis. Polysaccharides were highly concentrated in the epidermis and dermis of both species while proteins were highly concentrated only in the epidermis. Transmission electron microscopy (TEM) showed that the skin of both snakes consisted of keratins located in the epidermis. Some lipids and mucus were incorporated into the outer scale surfaces such that lipids were part of the fully keratinised hard layer of the snakes' skins. Lipids are probably responsible for limiting water loss and ion movements across the skin. Melanosomes from epidermal melanocytes were present only in Cerastes vipera. In aggregate, these results indicate that snakeskin may provide an ecological indicator whereby epidermal and integumentary specializations may be ecologically correlated.

Histology of the Skin of Three Limbless Squamates Dwelling in Mesic and Arid Environments

“…Though the scales of these three squamates varied considerably in geometry, the stratification was generally conserved. The two snakes studied exhibit similar overall morphology and are consistent with previous observations on snakes such as Orthriophis taeniurus (Maderson, 1965) Leptotyphlops dulcis, Tantilla gracilis, T. nigriceps, Sonora episcopa, and Virginia striatula (Jackson and Reno, 1975), Natrix tessellata and Cerastes vipera (Abo-Eleneen and Allam, 2011).…”

“…Polysaccharides were found distributed throughout the layers of the epidermis, except in the stratum germinativum , as well as in the dermis; thus, this observation is consistent with previous observations in lizards and snakes (Mohammed, ). Polysaccharides are found in the epidermis of metazoans and have been reported in the integument of cephalopods (Srinivasan et al, ), echinoderms (Katzman and Jeanloz, ), fish (Seno et al, ; Banerjee ; Mittal and Banerjee, ), and snakes ( Natrix tessellata and Cerastes vipera ; Abo‐Eleneen and Allam, ), these molecules have been hypothesized to work as intercellular cement (Henkart et al, ). In some tetrapods, such as amphibians, reptiles, and birds, epithelial polysaccharides serve to define integumentary features (Sengel, ; Mohammed, ; Abdeen et al, ).…”

“…Scales also vary and differ according to the location in the body region (Maderson et al, 1998), or according to environmental impact (Allam and Abo-Eleneen, 2012). In snakes the scaled skin is formed by two regions that contrast drastically in histology, a region formed by a series of elevated, thickened horny epidermal scales and another region formed by thin inter-scale hinge regions (Maderson, 1965;Gans, 1974;Alibardi and Toni, 2006;Abo-Eleneen and Allam, 2011). Anatomical details on the epidermal scales of snakes have been studied, such as the carbohydrate histochemical distribution (Natrix tessellata and Cerastes vipera; Abo-Eleneen and Allam, 2011), mucous cells in the epidermal hinge region and carbohydrate distributions in the epidermal cells (Xenochrophis piscator, Banerjee and Mittal, 1978).…”

The rhinoceros among Serpents: Comparative anatomy and experimental biophysics of Calabar burrowing python (Calabaria reinhardtii) skin

“…The morphology of the interscale and hinge region of the snake integument has been previously described (Abo-Eleneen & Allam, 2011), and the role of interscale mobility (particularly of the ventral scutes) during some forms of locomotion has been detailed (Baum, Kovalev, Michels, & Gorb, 2014;Gans, 1974;Hu, Nirody, Scott, & Shelley, 2009;Lissmann, 1950). No previous study has quantified the features of the interscale region, or documented interspecific variation in the hinge region (Table 2, Figure 5).…”

“…One of the characteristic features of a squamate reptile, the monophyletic group which includes snakes and lizards (Wiens et al, ), is the presence of thickened ectodermal scales (Chang et al, ). In terms of their material composition and basic histological properties there is little variation among snake scales either interspecifically or between different regions of the same snake (Baden & Maderson, ; Klein & Gorb, ), although, there are marked differences between the scales and the interscale, or hinge, regions (Abo‐Eleneen & Allam, ).…”