Several studies are concerned to study the mammalian tongue from the morphological standpoint, using modern techniques, in order to propose a functional hypothesis on food-tongue relationship during the successive feeding process. However, no enough data are available in the literature about the correlation between the tongue morphology and the feeding habits of many of the Egyptian reptiles. Therefore, the present study is conducted to clarify the morphological and histological appearance of the dorsal lingual surface of two Egyptian squamate reptiles having two different feeding habits; the insectivorous gecko, Tarentola annularis and the Egyptian vegetarian spiny tail lizard, Uromastyx aegypticus. The dorsal tongue surface is examined morphologically and by light and scanning electron microscopy (SEM). The results revealed that the tongue in both species is macroscopically different. At SEM, the dorsal lingual surfaces of both species are rich in lingual papillae of various shapes and sizes. In gecko, three types of lingual papillae are recognized; dome-shaped, leaf-shaped and broad scale-like papillae on the lingual apex, body and root of the tongue, respectively. In lizard, broad scale-like papillae are observed on the apex, meanwhile transverse parallel folds, broad and short folds, and leaf-like papillae are detected on the tongue body. Moreover, flattened scale-like lingual papillae are found on the lingual root. Histological examination revealed that the dorsal lingual epithelium in both species consists of stratified squamous type which is para-keratinized in gecko and non-keratinized in lizard. The present data indicated that the morphological and histological variations of both tongues may be related to their feeding habits. These results can give a contribution to the knowledge of the tongue anatomy and histology in two widely diffused species in Egypt.
Reptilia, Tongue, SEM, Light microscopy