Ultrastructure of the lingual epithelium of adult scincine lizard Chalcides ocellatus

In the present investigation, the histological and histochemical characteristics, as well as the ultrastructure of the lingual epithelium of the adult lizard Chalcides ocellatus, were investigated by light microscopy (LM) and scanning electron microscopy (SEM). Histological examination revealed taste buds and sensory papillae on the tongue tip and on the foretongue. The papillae were covered by stratified squamous epithelium and the core of the papillae is penetrated by connective tissues, pigment cells and striated muscle fibers. The acinar lingual glands appeared between the lateral sides of the papillae with increased number posteriorly. These glands stained purple with AB-PAS dorsally, and pink, with some purple cells, ventrally. SEM observations revealed three different types of lingual papillae, which were widely distributed over most dorsal surface of the tongue. The epithelial cells covering the surface of each papilla include smooth surface epithelial cells at the distal part of the papillae (free border) and cells with microridges interspersed with micropores at the intermediate portion of the papillae. Cells with densely distributed tall microvilli bearing extracellular mucus were noticed at the proximal portion of the papillae (near the base). Most of the surface of the bifurcated part of the tongue was relatively smooth with pitted and wrinkled surfaces (characteristic marks of the keratinized epithelium). Also the correlations between the structure and function were discussed in details.