Dorsal Surface of the Tongue of the Hazel Dormouse Muscardinus Avellanarius: Scanning Electron and Light Microscopic Studies/ Grzbietowa Powierzchnia Języka Orzesznicy Muscardinus Avellanarius: Badania Z Wykorzystaniem Mikroskopu Skaningowego I Świetlnego

Abstract

Abstract The dorsal surface of a hazel dormouse tongue was examined by scanning electron and light microscopy. The tongue of the hazel dormouse is elongated and widened in the proximal part. On the proximal one-third of the tongue a clear median groove is observed. The dorsal lingual surface was covered with five types of papillae: filiform, conical, fungiform, vallate and foliate. The arrangement, shape, size and direction of the filiform papillae vary depending on the region of the tongue. On the proximal part of the tongue, the filiform papillae are saw-like and tilted medioposteriorly, while on the distal part they have a fork-like shape and form a radial pattern with their processes oriented towards the center of the tongue. Fungiform papillae with single taste buds are evenly scattered on the anterior and middle part of the tongue body. On the root of the tongue, three star-like shaped vallate papillae are arranged in the form of a triangle and surrounded by conical papillae. A pair of foliate papillae are found on both edges of the posterior area of the tongue, forming three parallel folds separated by deep grooves. The dorsal surfaces of the vallate and foliate papillae are covered with hard-cornified epithelium, while the lateral surfaces have noncornified epithelium with numerous taste buds. The results of our studies show that the tongue structure of the hazel dormouse is more primitive in comparison with other rodents which is related to their phylogeny and feeding habits.