The tongue of Leopard Gecko (Eublepharis macularius): LM,SEM and confocal laser study

The leopard gecko is a crepuscular and insectivorous reptile. The role of the tongue in this reptile is fundamental for the prey capture and ingestion and is not related with eyes cleaning as usual in other geckos. The elongated tongue can be divided into a foretongue with a slightly bifurcated apex and a hindtongue. Scanning electron microscopy demonstrated that several different papillae are present on the dorsal surface, foliate and dome-shaped in the foretongue, becoming thicker and stouter with reduced interpapillary spaces in the lateral parts. The hindtongue is characterised by wide foliate papillae with indented margins and deep fissures of the mucosa. Light microscopy showed the presence of a stratified slightly keratinized squamous epithelium in the apex of the foretongue, a stratified non-keratinized squamous epithelium in the fore and in the hindtongue. In the foretongue, numerous muciparous caliciform cells were observed. Moreover, the presence of taste buds on the tongue ventral surface was demonstrated for the first time in this species and the confocal laser study revealed a strong immunoreactivity for the S-100 protein in the sensory cells. Therefore, the results obtained could give a contribution to the knowledge of the tongue anatomy and are a basis for eventual further studies regarding the feeding habits in a reptile become a popular pet.     

Investigations on the light and scanning electron microscopic structure of the lingual papillae in the angora goat (Capra hircus): II. Mechanical papillae

This study was conducted to examine the light microscopy (LM) and scanning electron microscopic (SEM) structures of mechanical papillae on the tongue in the Angora goat (Capra hircus). As study materials, the tongues of four adult female Angora goats were used. The samples were collected from the dorsal surfaces of the apex, body, root and torus of the tongue and the ventral surfaces of the lingual apex for light and scanning electron microscopic examinations. Three types of mechanical papillae were seen in Angora goat tongue: papilla filiformes, papilla lentiformes and papilla conicae.The filiform papillae were detected in the dorsal surface of the tongue from lingual apex to lingual torus, and in the ventro-lateral of the lingual apex and on both sides of the lingual torus. The morphological differences were observed in filiform papillae according to their location in the tongue. The lenticular papillae settled on the centre of the lingual torus. Two types of these papillae, irregular-round and pyramid-shaped were identified. The conical papillae were scattered all over the lingual torus, except for the central part and were also seen on the root of the tongue. In the light microscopic examination, it was found that mechanical papillae had a stratified squamous epithelium and a varying degree of keratin layer on epithelial surfaces. In this study, by examining the light and scanning electron microscopic structure of the mechanical papillae in the Angora goat tongue, their similarities and differences with other domestic and wild ruminant species were determined.     

Ultrastructure of Lingual Papillae in Common Chimpanzee (Pan troglodytes) Foetus,Newborn and Adult Specimens

Among primates, the two recognized species of chimpanzees (common chimpanzee, Pan troglodytes; pygmy chimpanzee, Pan paniscus) are considered to be the most similar to humans. Importantly, in mammals, the food intake behaviour largely determines the tongue morphology, including the type, proportion and distribution of gustatory and non‐gustatory tongue papillae. The lingual papillae form during its development and mature in post‐natal life depending on the different feeding. In this study, we have used scanning electron microscopy to analyse the age‐related changes in the lingual papillae of foetal, newborn and adult P. troglodytes. Four main types of lingual papillae, denominated filiform, fungiform, foliate and vallate, and one subtype of filiform papillae called conical papillae, were found. The main age‐related changes observed in all kinds of papillae were a progressive keratinization and morphological complexity along the lifespan. During the foetal period, there was scarce keratinization, which progressively increases in young animals to adulthood. The number of filiform increased with ageing, and both filiform and fungiform papillae in adult tongues are divided into pseudopapillae. On the other hand, the vallate papillae vary from smooth simple surfaces in foetal tongues to irregular surfaces with grooves and pseudopapillae (microscopic papilla‐shaped formations within the papilla itself) in adults. These results describe for the first time the age‐related variations in the three‐dimensional aspect of lingual papillae of the chimpanzee tongue and provide new data to characterize more precisely these structures in the human closest specie.     

Morphological Study of the Persian Leopard (Panthera pardus saxicolor) Tongue

This study described the morphological features of the Persian leopard (Panthera pardus saxicolor) tongue using light and scanning electron microscopy techniques. The keratinized filiform papillae were distributed all over the entire dorsal surface of the tongue and contained small processes. They were changed into a cylindrical shape in the body and conical shape in the root. The fungiform papillae were found on the apex and margin of the tongue. Few taste pores were observed on the dorsal surface of each papilla. The foliate papillae on the margins of the tongue were composed of several laminae and epithelial fissures. Taste buds were not seen within the non‐keratinized epithelium. The vallate papillae were six in total and arranged in a “V” shape just rostral to the root. Each papilla was surrounded by a groove and pad. Taste buds were seen within their lateral walls. Lyssa was visible on the ventral surface of the tongue tip and was found as cartilaginous tissue surrounded by thin connective tissue fibres. The core of the tongue was composed of lingual glands, skeletal muscle and connective tissue. These glands were confined to the posterior portion of the tongue and were composed of many serous cells and a few mucous cells. The results of this study contributed to the knowledge of the morphological characteristics of the tongue of wild mammals and provided data for the comparison with other mammals.     

scanning electron microscopy of lingual papillae in the common shrew, Sorex araneus, L

The dorsal surface of the tongue of the adult common shrew (Sorex araneus L.) was examined by scanning electron microscopy. As in the other insectivores, three types of lingual papillae were observed: filiform, fungiform and vallate papillae. The filiform papillae represented the most numerous type of lingual papillae. The characteristic feature of the filiform papillae, covering the apex and corpus of the tongue, is the two processes tilted to the root of the tongue. The filiform papillae on the lingual apex are reduced in size and structure. Five to six fungiform papillae are placed symmetrically along the left and right border of the corpus of the tongue. Two large oval vallate papillae are located on the radix of the tongue. The posterior surface of the tongue in common shrew is covered with a smooth mucosa with the openings of the serous glands.     

Morphological characterization of Horsfield’s treeshrew Tupaia javanica lingual papillae: Light microscopy and scanning electron microscopy studies

The Horsfield's treeshrew (Tupaia javanica) is one of the shrews found on the island of Java that mainly feeds on fruits and occasionally insects. This shrew has an important role in the ecosystem as it spreads plant seeds and controls insects. To this day, there is no available knowledge about the structure of Horsfield's treeshrew's tongue. Therefore, the aim of this study was to provide data on the tongue structure of the Horsfield's treeshrew through two different methods. We investigated the tongue morphology and lingual papillae distribution of Tupaia javanica using 1) scanning electron microscopy (SEM) for microscopic structure and 2) histology for microscopic organization. Our macroscopic results revealed that the tongue of Tupaia javanica can be divided into three parts: apex, corpus and radix. The dorsal surface of the medial corpus is the median groove extending to the radix. Observation using SEM and light microscopy (LM) showed that the apex of the tongue bears three types of papillae: scale-like filiform, small filiform and fungiform. These are rosette filiform papillae, cornflower filiform papillae, conical papillae and fungiform papillae in the corpus. Meanwhile, the radix contains small filiform papillae, scale-like filiform papillae, vallate papillae, conical papillae and fungiform papillae. On the lateral posterior radix, Weber's gland reacts positively to PAS reaction. Taking together, our research shows that there are variations in the papillae on the tongue surface of Horsfield's treeshrew, and the variations of these papillae are very dependent on the pattern, type of food and the function of the tongue.     

Characteristics of Dorsal Lingual Papillae of the Bactrian Camel (Camelus bactrianus)

The morphology of dorsal lingual papillae of the Bactrian camel (Camelus bactrianus) was studied by using light and scanning electron microscopy. Filiform and lenticular papillae were considered as mechanical papillae but fungiform and vallate papillae were considered as gustatory papillae. Filiform papillae were distributed mostly in the anterior two-thirds region of the tongue. Each filiform papilla consisted of one primary papilla and a few smaller secondary papillae. Lenticular papillae were distributed on the torus linguae. The larger papillae were arranged in two parallel lines medially whereas the smaller papillae were laterally located. Most of the fungiform papillae were found on the lateral margins of the anterior two-thirds of the tongue. These papillae were small and round. Intra-epithelial taste buds were located on the dorsal surface of each papilla. The vallate papillae were arranged in two rows on each rim of the torus linguae. Each round- and flat-shaped vallate papilla was surrounded by a prominent gustatory groove and an annular pad. A few taste buds were observed in the lateral epithelium of the papillae. The keratinization of the covering stratified squamous epithelium of the mechanical lingual papillae was relatively thicker than those of the gustatory papillae. The lingual papillae of the Bactrian camel exhibited some different characteristics from other domestic ruminants. These morphological characteristics of the tongue of the Bactrian camel might have evolved to assist the camel in prehension and manipulating of the inorganic stiff plants that grow in its environment and therefore might relate to the feed and feeding habits of the animal.     

The Tongue Dorsal Surface in Fish: A Comparison Among Three Farmed Species

The oral cavity of vertebrates has a very important role in many functions strictly related to the food processing. Two species, sea bass Dicentrarchus labrax and seabream Sparus aurata, are mainly involved in the aquaculture industry in the mediterranean area; moreover, the white seabream Diplodus sargus sargus was recently chosen as the best candidate for the diversification of species of commercial interest. This investigation was carried out, using the standard procedures for light and scanning electron microscopy, to analyse the morphology of the tongue dorsal surface in order to show whether relationships are present between the tongue morphology and the nutritional choices of these species. In all the three investigated species, three different areas were observed on the dorsal lingual surface: an apex, a body and a root. In the sea bass D. labrax, numerous caninelike teeth, organized in pads, were present along the dorsal surface. The presence of numerous taste buds, scattered on the tongue, was shown. In the seabream S. aurata, the apical part of the tongue is inserted in a pouch with a characteristic medial ridge on the body surface. Numerous taste buds were scattered on the whole surface. In the white seabream D. sargus sargus, a pouch partially covering the apex was clearly observed. In the pouch, filiform‐like and foliate‐like papillae can be distinguished. The results show the important role of the fish tongue in the food ingestion process, demonstrating the interaction of food processing, taste and morphological characteristics.     

Morphology of the tongue and laryngeal entrance in the Common pheasant (Phasianus colchicus); a light and scanning electron microscopic study

The present work was carried out to describe morphological features of the tongue and laryngeal entrance of the Common pheasantPhasianus colchicus, using light and scanning electron microscopy. The lingual apex was taper-shaped with a shallow median sulcus. A V-shaped papillary crest with 15–20 caudally directed conical papillae was located between the radix and corpus linguae. The second row of papillae consisting of three caudolaterally directed conical papillae was arranged caudal to the main papillary crest. The mons laryngealis was equipped caudally with a double-layer of large conical papillae as pharyngeal crest, and few small conical papillae were seen around the glottis. Scanning electron microscope (SEM) observation showed that the apex linguae and corpus were covered with compact filiform papillae, while the radix linguae were free of papillae. Numerous openings of salivary gland can be seen on the radix linguae and mons laryngealis at higher magnification. On histological sections, all parts of the tongue and mons laryngealis were covered with a keratinised stratified squamous epithelium. The keratinised layer became thinner rostro-caudally. The simple alveolar salivary glands were distributed in the submucosa from the apex linguae to the radix linguae as well as the mons laryngealis. PAS staining revealed mucin-secreting activity of this glands. According to the findings, although the tongue and laryngeal entrance of the Common pheasant is characteristics of a galliform bird, it has some features similar to passeriformes and falconiformes.     

Etude Morpho-Structurale des Papilles Linguales chez le Buffle (Bubalus bubalis)

Morphostructural characteristics of lingual papillae in buffalos The morphostructural characteristics of lingual papillae in 30 adult buffalos were studied by SEM. In this species, dorsal lingual surface papillae shos different shape so that their classification is complicated. Topography and morphology of conical and vallate papillae presents significant aspects. Particularly, the conical papillae have a different morphological organization when they are localized over the side of the tongue apex or over dorso-lateral tract of the tongue body. The functional aspects are discussed.     

Morphological and functional comparison of lingual papillae in suckling and adult feral cats: Forensic evidence

Feral cats are considered as strays and are more likely to hunt in the street. We investigated the effect of environmental adaptations on the structures of lingual papillae in feral cats, which could be used as forensic evidence for their identification. There are no reported studies about the structural comparison of lingual papillae between suckling and adult feral cats. The present study described the lingual papillae of both suckling and adult cats macroscopically and microscopically via light and scanning electron microscopy. A total of nine tongue samples each for suckling and adult feral cats were examined grossly and histologically. Papillae distributions of suckling cats were similar to those observed in adult cats. Meanwhile, the shapes of those papillae were markedly different from that of corresponding papillae in adults. The change in taste bud position and size seemed to be related to the progressive growth of the papillae between adult and suckling cats; absence of taste buds in foliate papillae of feral cats at any stage; and marginal papillae which were a characteristic feature for all suckling cats. All previous elements could be affected by the specific feeding behaviour and mastication mode adaptation in suckling and adult feral cats which might help to identify suckling and adult feral cats among other breeds and animal species. We anticipate these findings may provide promising forensic evidence to discriminate between adult and suckling feral cat remains as well as prediction of environmental harshness and feeding behaviour.     

Morphology of the Lingual Dorsal Surface and Oral Taste Buds in Italian Lizard (Podarcis sicula)

With 4 figures The Italian lizard (Podarcis sicula) is the most diffused reptile in Italy, but it is also present in other European countries. This lizard belongs to the Lacertidae family, lives near walls, slants and along the borders of the paths; its diet includes bugs and aracnids. No data are so far available in literature about the three‐dimensional morphology of the tongue of Podarcis sicula, therefore the aim of the present paper was to study by scanning electron and light microscopy the three‐dimensional characteristics of the dorsal lingual surface and moreover the presence of chemosensory receptors like the taste buds in the oral cavity. Our results demonstrate that the Podarcis sicula tongue is a triangular muscular membranous organ, dorsoventrally flattened and that three different areas can be observed: a bifid apex, a body and a root. No papillae were observed in the apex, characterized by a flattened mucosa and by two deep median pouches. In the body cylindrical papillae with a flat surface are present, aborally gradually substituted by imbricated papillae. Foliate‐like papillae were observed in the lateral parts of the tongue body. No sensory structures were showed on the lingual dorsal surface, while they were numerous in the oral cavity, particularly on the gingival epithelium. The light microscopy shows, on the dorsal surface, a stratified pavimentous not keratinized epithelium, conversely keratinized along the ventral surface. Many caliciform cells on the lateral parts of the papillae, deputed to the secretion of mucus, were also observed. Therefore, the results obtained in this paper could give a contribution to the knowledge of the tongue anatomy in a species widely diffused in different European countries and could be of help for clinical purposes in reptiles.     

Histomorphological features of the tongue of the Eurasian teal (Anas crecca)

This study presents the histomorphological features of tongue in Eurasian teal (Anas crecca); the smallest extant dabbling duck. Heads of four adult males and four adult females were used in this study. The results illustrate a tongue with three different parts; the apex with a lingual nail in ventral surface, the body with a lingual prominence in caudal part and some large and small conical papillae in lateral sides and the root, that was covered with many conical papillae in different sizes. Histological results revealed two types of keratinized and non‐keratinized epithelium covering parts of the tongue. The lingual salivary glands were observed in the lamina propria of the body and root of the tongue showed strongly periodic acid–Schiff (PAS)‐positive reaction. The yellow adipose tissue was located under the lamina propria on the body and root of the tongue. The filiform papillae between the conical papillae of the body were arranged densely. The sensory organs, which contain sensory receptors (Grandry and Herbst corpuscles), were located in the lamina propria of the body of the tongue. In conclusion, the anatomical and histological structure of the Eurasian teal’ tongue was generally similar to its family members such as domestic goose and duck but showed some differences that may be adoptions to the bird's habitat and mode of feeding.