Morphological study by scanning electron microscopy of the lingual papillae in the Middle East blind mole rat (Spalax ehrenbergi, Nehring, 1898).

There is no definite information about the tongue morphology of blind mole rats owing to spreading of these animals to only a certain habitat. For this reason, we aimed to examine the morphological structure of the tongue by scanning electron microscopy (SEM) in this species. In this study, the tongues of four blind mole rats were used and the morphology of its lingual surface, different types of papillae, their characteristics and topographical distribution was described. Three types of papillae (filiform, fungiform and vallate) and lingual prominence were observed. The dorsal surface of the tongue was covered by filiform papilla; and filiform papillae demonstrated the most numerous type of lingual papilla. Fungiform papillae were rounded in shape and randomly distributed particularly on the anterior and medial region. In addition, each fairly convex fungiform papilla was surrounded by a continuous circular pad like a crown. The two oval vallate papillae were situated symmetrically on the posterior region and obliquely to the median line of the tongue. The body of vallate papillae was surrounded by a continuous trench and mucosal folds. The lingual prominence between medial and posterior region and a transversal groove just in front of it were observed. Furthermore, a limited tuber and root based diet and gnawing have together resulted in similarity of the tongue of the rodent, giving it some characteristics typical of a herbivore and an insectivore.