Electron microscopy of the scale of 2 japanese snakes 1. trimeresurus flavoviridis flavoviridis and trimeresurus okinavensis
Kikuchi, S.; Sawai, Y.; Toshioka, S.; Matsu, T.; Okuyama, Y.
Snake 13(1): 6-15
Scales of the 2 spp. of snakes, T. flavoviridis flavoviridis (Hallowell, 1860) and T. okinavensis (Boulenger, 1892) were examined by scanning electron microscopy. Scales were different in shape and size in different parts of body. Scales of T. flavoviridis flavoviridis, in general, were larger and elongated pentagonal in contour, and those of T. okinavensis smaller and broadly pentagonal. On the dorsal surface of scale, there existed a spindle-shaped ridge along the midline and numerous papilla-like projections on the lateral and terminal parts in T. flavoviridis flavoviridis, whereas elliptical papilla-like projections covered all the surface in T. okinavensis. A pore was present .apprx. 1 mm from the distal end of the keel in T. flavoviridis flavoviridis and .apprx. 0.7 mm in T. okinavensis. Many nerve-like threads originated from the pore and their finer threads were distributed all over the surface of keel. The so-called apical pit was not a pit but a shallow depression. At the apical pit the cuticle layer was thin and had a small number of cells, so the scale was almost transparent at the apical pit. The keel had the shape of the letter S at the apical pit. The S-shaped part of keel appeared to function to regulate the length of keel when the scale moves at the distal end. The ventral and the subcaudal plates seemed to function for the snakes to move and to support the body on the ground and trees. When considering the morphology of scale, the snakes can probably feel the environmental stimuli such as vibration, sound and humidity through the scale while moving.