Light and scanning electron microscopic study on the tongue and lingual papillae of the common raccoon, Procyon lotor

Lingual morphology of domesticated Asian small-clawed otters in Yogyakarta, Indonesia

This study aimed to observe the lingual morphology of the domesticated Asian small-clawed otter, Aonyx cinereus (A. cinereus), from Yogyakarta, Indonesia. Six domesticated A. cinereus adults were obtained from a local otter breeder in Yogyakarta, with no regard to sex. The animals were acclimated to the laboratory for one day, following this, the animals underwent macroscopy identification and scanning electron microscopy (SEM) and light microscopy (LM) analysis. Macroscopically, the tongue of domesticated A. cinereus is divided into three parts: the apex, corpus, and radix. The apex is the shortest part and can move freely. A median groove is bent along the corpus. Typically, the radix contains circumvallate papillae and the epiglottic valleculae. The SEM and LM observations revealed that the lingual morphology of A. cinereus consisted of two types of papillae: mechanical papillae (horny filiform, leaf-like filiform, bifid filiform, trifid filiform, elongated leaf-like filiform, triangular filiform and conical papillae) and gustatory papillae (fungiform and circumvallate papillae). The lingual glands consisted of Weber's glands and von Ebner's glands secreting acid and neutral mucins. Collagen fibres are found in the lamina propria and muscular layer. In conclusion, the papillae of the Asian short-clawed otter have the same structure as those of other Mustelidae family members.

The tongue of the red panda (Ailurus fulgens fulgens Cuvier, 1825)-a stereoscopy, light microscopy and ultrastructural analysis

In the light of recent molecular studies, there are two phylogenetic species of the red panda (Ailurus fulgens): Ailurus fulgens fulgens and Ailurus fulgens styani. The red panda belongs to the endangered species living in the wild only in Asia and is included in the CITES list. Although the biology and diet of this species has been extensively described, the histological structure of the tongue and lingual glands has not yet been characterized in detail in relation to the lifestyle of this mammal under specific conditions and as a basis for comparative anatomical studies of the biodiversity of endemic species. Study samples were collected from two adult males of Ailurus fulgens f. held in Wrocław Zoological Garden. Both tongues were examined macroscopically; moreover, samples with lingual papillae for light microscopy and scanning electron microscopy (SEM) were collected from the apex, body and root of the tongue. Both tongues of the Ailurus fulgens f. males were approximately 9 cm long. The dorsal lingual surface was covered with mechanical and gustatory lingual papillae. Filiform papillae were observed on the apex and the body of the tongue, while small conical papillae were observed on the root of the tongue. An elongated, 1-1.5 cm long cylinder-shaped lyssa was observed in the ventral part of the apex. Moreover, most numerous and largest round in shape fungiform papillae were observed on the apex and on the border of the body and root of the tongue, located directly rostrally to 12-13 round and oval in shape vallate papillae. The SEM study showed that filiform papillae on the apex had several long secondary processes, while filiform papillae on the body of the tongue were taller and their secondary papillae were shorter than the equivalent structures on the apex of the tongue. The SEM study showed numerous taste pores on the surface of the fungiform papilla, while irregular surface of the vallate papillae, however some of them had smoother surface. Mixed glands (comprised of mucous acini and serous acini) were present within the vallum (within the connective tissue core) of the vallate papilla. Beneath the papillae more serous glands were observed, while the posterior lingual glands in the caudal part of the root of the tongue were mucoserous (mucous units were prevalent). A characteristic feature of the tongue of Ailurus fulgens f. was the presence of lyssa, which is comparable to other representatives of Carnivora, but the number of vallate papillae was individually variable. The lack of strongly developed mechanical conical papillae probably may be related to the type of plant food that is particularly dominant in red panda. Further differences between Ailurus fulgens f. and Ailurus fulgens s. cannot be excluded. The results of these studies may be useful especially for veterinarians specializing in working with exotic animals and people dealing with wildlife conservation.

Three-dimensional study of the lingual papillae and their connective tissue cores in the Nile fox (Vulpes vulpes aegyptica) (Linnaeus, 1758)

The Nile fox (Vulpes vulpes aegyptica) is the largest Egyptian fox being distributed in different geographical regions in Egypt. The current study aims to investigate the three-dimensional features of the lingual papillae and their connective tissue cores (CTCs) in the Nile fox by using scanning electron microscopy. Five types of lingual papillae were present on the dorsal aspect of the tongue: filiform, conical, fungiform, vallate, and foliate. Generally, the filiform papilla consisted of a main papilla and several accessory processes emerged from its basal part. Filiform papillae differed in their length, shape, and number of accessory processes according to the region of the tongue. Two types of filiform CTCs were present; either conical-shaped or consisted of a main core and several accessory cores. Two types of conical papillae and two types of conical CTCs were demonstrated; elongated triangular-shaped and large conical-shaped. In addition, two types of fungiform papillae were demonstrated; rounded-shaped and elongated fungiform papillae. The fungiform CTCs were thick columnar in shape with several parallel vertical folds. Six vallate papillae were present, they were surrounded by a groove and either conical papillae or an annular pad. The surface of the vallate CTCs and their surrounding pad had small protrusions. The foliate papillae were represented by 5-6 laminae separated by grooves. The foliate CTCs appeared as oval grooves limited by laminar projections. Regional variations of the filiform papillae and the presence of three types of gustatory papillae suggest specialization of the Nile foxes' tongue to their omnivorous diet.

Three-dimensional aspects of the lingual papillae and their connective tissue cores in the tongue of rats: a scanning electron microscope study

The aim of the present study was to describe the tridimensional morphological characteristics of the lingual papillae and their connective tissue cores (CTCs) in Sprague Dawley rats. Four types of papillae were reported on the dorsal surface. Filiform papillae were distributed on the tongue surface and after epithelial maceration a conic and multifilamentary shape of the CTCs was revealed. Fungiform papillae were reported on the rostral and middle regions covered by a squamous epithelium. After the removal of the epithelium, the shape of a volcano with the taste orifice at its top was noted. Foliate papillae were composed of five pairs of epithelial folds situated on the lateral-caudal margin of the tongue. After the removal of the epithelium, they were shown to be limited by thin laminar projections. The vallate papilla with an oval shape was present in the caudal region and delimited by an incomplete groove. The morphological characteristics of the lingual papillae of Sprague Dowley rats, three-dimensional SEM images, and the types of papillae on the dorsal surface were similar to those reported previously in other rodent mammals. The maceration technique revealed the details of extracellular matrix with varied shapes form of connective tissue cores.