Comparative histological and ultrastructural features of the tongue of the mallard domestic duck, Anas platyrhynchos f. domestica, Anatidae (Linnaeus, 1758) in different two age stages (post-hatching [P2] and adult female) captured from Egypt

The domestic duck is classified as a specialist filter-feeder bird living in the water. These birds also use grazing and pecking as terrestrial feeding methods. The tongues of domestic ducks, similar to those of other Anseriformes, exhibit numerous types and shapes of mechanical papillae that serve a number of purposes when collecting food. The current study attempts to describe the morphological characteristics of the tongue as well as the mechanical papillae's development. In addition, the study aims to determine whether the papillae observed post-hatching (P2) exhibit similar morphology to those found in adult female avian species, as well as to investigate the readiness of the tongue to fulfill its feeding function following hatching. The comprehensive examination of lingual mucosa is examined about the structural modifications necessary for this variety of feeding activities. In this study, the tongues of nine young (P2) and adult female were used. The tongue had three distinct parts: the apex, which had a lingual nail on its ventral surface; the body, which exhibits numerous small and large conical papillae on its lateral sides and a lingual prominence in the caudal region; and the root, which is covered with numerous conical papillae of varying sizes. Conical, filiform, and hair-like mechanical papillae, the three types of food filtration apparatus, are present in both stages. The intraoral transfer involves several structures, including the median groove, lingual combs, and the rostral border of the lingual prominence. The rostral border of the lingual prominence is characterized by distinct rows of conical papillae. The histological analysis demonstrated the presence of both keratinized and nonkeratinized epithelium on different tongue regions. The lingual salivary glands in the rostral and caudal lingual salivary glands exhibit a pronounced periodic acid-Schiff-positive reaction. Additionally, the yellow adipose tissue and sensory receptors, namely the Grandry and Herbst corpuscles, which collectively form the bill-tongue organ that monitors the movement of food. These results conclude the presence of microstructural species-specific alterations in specific tongue areas of domestic ducks' lingual mucosa. These modifications are formed by the filtering mechanism and terrestrial feeding mechanisms, such as grazing or pecking. Following hatching, the tongue of the domestic duck undergoes significant development, primarily in preparation for grazing activities. The anatomical and histological structure of the young (P2) tongue exhibited similarities to that of the adult female domestic duck while also displaying certain variations that could potentially be attributed to the bird's habitat and mode of feeding. RESEARCH HIGHLIGHTS: The results of this study concluded that the domestic duck exhibit a complex tongue structure characterized by the arrangement and morphology of its mechanical papillae, the presence of the lingual prominence with distinctive shape and the lingual comb. These features are believed to be adaptations that enable the duck to actively and efficiently filter food particles from water, serving as its primary feeding mechanism. Additionally, the tongue of domestic ducks is specifically adapted to facilitate various terrestrial activities, such as grazing and pecking. This adaptation is achieved through the presence of conical papillae and a lingual nail. These investigations facilitate our comprehension of both the anatomical and histological characteristics of the domestic duck tongue, as well as enhance our understanding of bird adaptations to various feeding mechanisms.

Tongue microarchitecture and functional characterization of the lingual papillae in the desert hedgehog (Paraechinus aethiopicus)

The present work attempted to provide a comprehensive description of the morphoanatomical, histological, and ultrastructural characteristics of the tongue in the desert hedgehog (Paraechinus aethiopicus), and to correlate lingual modifications to the feeding lifestyle. Five adult male hedgehogs were utilized in our investigation. The macroscopic observations revealed elongated, with a moderately pointed apex, tongue and the tongue dorsum lacks both lingual prominence and median sulcus. The main subdivisions of the tongue are radix linguae (root), corpus linguae (body), and apex linguae (apex). The tongue dorsum carries two types of mechanical (conical and filiform) and gustatory (fungiform and circumvallate) papillae. The lingual apex is characterized by the existence of a unique encapsulated muscular structure. Additionally, the lingual glands were interposed between the muscular strands and no lingual glands were detected on the lingual apex. The dorsal surface of the lingual apex exhibited the highest level of keratinization as revealed by histochemical staining while the root showed moderate staining. The topography of the tongue was investigated by scanning electron microscopy (SEM). The obtained results are important to provide basic knowledge that can contribute to better understanding of the nourishment, feeding habits and behavior in this species. Furthermore, the addition of the newly investigated species may help us to determine the evolutionary relationships among species.

Lingual Ultrastructural and Histochemical Study in the Patagonian Mara (Rodentia: Caviidae, Dolichotis patagonum) in Relation to Other Hystricomorphs

The study describes the ultrastructure of the tongue in the Patagonian mara (Dolichotis patagonum) using light and scanning electron microscopy. Histochemical methods were used for evaluation of lingual salivary glands. The tongue is divided into a small and rounded apex, a narrow corpus, and a significantly wider radix, with a well-developed lingual prominence. The tip of the apex is free of papillae. The caudal part of the apex and the corpus are covered by filiform papillae. Round fungiform papillae are scattered among them. Papillae on the narrow stalk are conical. The radix contains caudally bent papillae forming wide flat prominences, slender, hook shaped filiform papillae, foliate papillae, and two oval vallate papillae. Taste buds were found on the lateral sides of the foliate and vallate papillae. Purely serous salivary glands are beneath the vallate and foliate papillae. Serous acini and mucous tubules are in the lingual radix. The Patagonian mara is the only hystricomorph rodent with described hyaline cartilage strengthening the lingual radix. Some typical signs of adaptation to herbivorous diet were found. The structure of the tongue is adapted to grass-feeding, as grasses form the main component of their diet.

Tongue of the Egyptian Endemic Bridled Skink (Heremites vittatus; Olivier, 1804): Gross, Electron Microscopy, Histochemistry, and Immunohistochemical Analysis

The present study used light and scanning electron microscopy to describe the integrative morphological description of the tongue and laryngeal mound of Heremites vittatus, an endemic lizard of Saharan Africa. Additionally, ultrastructure, histology, histochemistry, and immunohistochemical approaches were used to characterize the lingual apparatus adaptations. In the present study, Heremites vittatus consisted of a complex lingual papillary system in which the ventral apical surface of the foretongue comprised conical papillae. The dorsal surface consisted of different filiform papillary (papillae filiformes) types: the anterior section had two types (bifid and pointed), and the posterior section had four types (triangular, trifid, quadrifid, and pentafid) papillae. The dorsal midtongue surface exhibits scale-like, serrated filiform papillae with anterior gland openings. The hindtongue consisted of two overlapping filiform papillae: scale-like, board-serrated papillae on the median portion and finger-like papillae on the wings. The dorsal surface of the laryngeal mound had 18 longitudinal folds with glandular openings. Histologically, the foretongue was covered by a slightly keratinized layer that was absent in the mid- and hindtongue. The lingual glands were absent from the foretongue but present in the interpapillary space in the mid- and hindtongues. We observed a few rounded taste buds in the conical papilla epithelium. Histochemical analysis revealed strong glandular Alcian Blue (AB)-positive and Periodic Acid-Schiff (PAS)-positive reactions. Immunohistochemistry showed strong cytokeratin immunopositivity in all parts of the tongue. In conclusion, the obtained data about the lingual characterizations have been consistent with the active foraging behavior of the species and its environmental conditions.

Scanning electron microscopic characterizations of the tongue of the Nubian goat (Capra aegagrus hircus): A specialized focus on its papillary system adaptation to Egyptian environmental conditions

The current investigation was focused on describing the gross and scanning electron features of the Nubian goat (Capra aegagrus hircus) tongue, with new insights into its papillary adaptation to the Egyptian environment. The elongated tongue had a rostral free and the caudal fixed. The ventral apical surface is classified into the smaller rostral papillary region on the tip and the larger non-papillary region by the U-line of filiform papillae. Functionally, there are two papillary types: mechanical (filiform, conical and lentiform in addition to the longitudinal row of large conical papilla on the lateral of the body) and gustatory (fungiform and circumvallate). Filiform papillae were densely distributed on the dorsal surface of the apex and body, and on the lateral apical border and lateral surface of the body and root, in addition to the ventral surface of the tip. This filiform papillary system gives a raspy appearance to the dorsal surface. The conical and lentiform papillae were limited to the torus linguae. Circumvallate papillae are surrounded by an annular groove and slightly vallum. The lingual root was devoid of any papillae. Lingual papillary subtypes are filiform papillae (elongated and triangular), conical papillae (elongated and oval) and fungiform papillae (round and ovoid). The investigated Nubian goat may have developed a specialized papillary system due to regional differences in the distribution, structure and subtypes of the system, allowing it to adapt to the dried grasses and leaves of trees and bushes that are available in Upper Egypt's dry, hot climate.

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.

Morphological tongue and palate characterizations in Trachemys adiutrix (Vanzolini, 1995) turtles

Morphological studies on the oropharyngeal cavity of turtles are an interesting tool in understanding evolutionary processes associated with feeding habits. There is paucity of morphological information on the oropharyngeal cavity of the Trachemys adiutrix turtle. Thus, the aim of this study was to describe the tongue and palate morphology of T. adiutrix to establish a standard model for the species, providing information that may improve knowledge on the species feeding habits. Gross dissection, light microscopy and scanning electron microscopy assessments of 11 specimens were carried out. The tongue of T. adiutrix is triangular with a slightly rounded apex and broad base and lingual papillae widely distributed throughout the entire dorsal surface. The palate is composed of bony structures, displaying a triangular apex with one pair of choanae and palatine raphe that begin in the middle region, dividing the two openings. The body was elongated and smooth. The root was wrinkled and opened into the oesophagus. The tongue was lined by non-keratinized stratified squamous epithelium, rich in mucous cells and a large number of different-shaped papillae and taste buds. The palate was mainly lined by a pseudostratified cylindrical ciliated epithelium rich in mucous cells. In conclusion, the tongue and palate characteristics of T. adiutrix include evidence that these animals are semiaquatic, displaying morphological characteristics associated with aquatic and terrestrial trophic ecology, similar to that observed in other semiaquatic and terrestrial chelonian species.

Structural and Ultrastructural Characteristics of the Spix's Yellow-Toothed Cavy (Galea spixii, Wagler, 1831) Tongue

The tongue is a fundamental organ in feeding, vocalization, and grooming. It is characterized by evolutionary adaptations reflected by diet, habitat, and function. Rodents are a very diverse mammalian order and the tongue's morphology varies in size, form, and presence of papillae. This work aimed to describe the morphological and ultrastructural aspects of the tongue of Spix's yellow-toothed cavy (Galea spixii, Wagler, 1831). Tongues of Spix's yellow-toothed cavies were analyzed with light microscopy, scanning, and transmission electron microscopy. The results showed that the tongue was divided into apex, body, and root. There were different types of papillae, such as vallate, foliate, laterally placed fungiform, fungiform, filiform, and robust filiform. The epithelium was organized into layers, including keratinized, granulous, spinous, and basal, below were lamina propria, and musculature, which evolved mucous and serous gland clusters. The tongue of Spix's yellow-toothed cavy was structurally and ultrastructurally similar to other rodents and had papillae with similar morphologies to other Caviidae species. However, the presence of robust filiform papillary lines and laterally placed fungiform papillae showed the main differences from other species. This was the first description of the tongue of Spix's yellow-toothed cavy.

Lingual papillary system of the Egyptian mouse-tailed bat (Rhinopoma hardwickii): New insights to its feeding strategies using scanning electron microscope, and immunohistochemical analysis of keratin

The current investigation described the ultrastructural and histological features of the lingual papillary system in 14 adult Rhinopoma hardwickii using scanning electron and light microscopy, and immunohistochemical staining of keratin. Three types of lingual papillae were recognized; one filiform mechanical and two gustatory (fungiform and circumvallate) of three directions: posterior, posteromedian, and median. Five filiform papillae subtypes were observed in four regions. The lingual tip had numerous giant filiform papillae. The lingual root was divided into two regions, an anterior papillary and a posterior non-papillary region that had only three circumvallate papillae in a triangular pattern. Histologically, the papillae exhibited detached thick keratin that spread over the dorsal epithelial surface. The dorsal surface of the root had stratified keratinized circumvallate papillae. Concerning the pan-cytokeratin (CK) antibody staining, moderate CK expression was observed in the superficial corneal layer of the apical lingual mucosa. While the superficial corneal cell layer in both body and root exhibited increasing of CK antibody. Morphometrically, there was a significantly increased, region-specific number of triangular, pointed filiform papillae, which were relatively increased in length and width. However, the round conical blunt filiform papillae and fungiform papillae were sparse. We concluded that our results showed distinguished adaptations in the lingual structure and its different papillae established on the nutritional and energetic demand of this bat species. This lingual adaptation is summarized in number, position, taste buds, direction, ultrastructural features, and histological that concerned with its ability in eating during the night flight.

Structural and Ultrastructural Changes in the Tongue of mdx Mice

The mdx mouse is an experimental model of Duchenne muscular dystrophy, a genetic disorder characterized by progressive muscular degeneration which affects the oral cavity musculature, and promotes difficulty in swallowing. This study aimed to describe morphological, structural, and ultrastructural changes in the tongue mucosa and musculature of mdx mice. Forty six-month-old mice were divided into two groups: Control C57bl/10 (n = 20) and mdx C57bl/10mdx (n = 20). The tongue was dissected and analyzed with light microscopy, scanning electron microscopy, and transmission electron microscopy techniques. Our results showed conical and triangular filiform, fungiform, foliate, and vallate papillae, and their connective tissue cores. The epithelium layers identified were corneum, granulosum, spinosum, and basale. The mdx group had a thicker epithelium. Lamina propria was composed of reddish and greenish collagen. In mdx, collagen was present in the musculature of the tongue's body and in the muscular tissue between mucous and serous glands of the caudal region. Musculature was also characterized by a shorter length of sarcoplasmic invaginations, myocytolysis in mitochondrial groupings, and inflammatory focus. In conclusion, the tongue of 6-month-old mdx mice had morphology, structure, and ultrastructure revealed, showing higher wear of filiform papillae indirect reflex from the muscular degeneration process.

Identification of the Lingual Papillae in the sugar glider (Petaurus breviceps) by scanning electron microscopy and light microscopy

A morphological description of the sugar glider's (Petaurus breviceps) tongue was obtained from five individual sugar gliders and analysed under a scanning electron microscope and a light microscope using four methods of staining. The tongue has a noticeably elongated structure with three regions: apex, corpus and radix. Transition to the corpus is indicated by the sulcus medianus linguae and the frenulum on its ventral surface. The dorsal tongue displayed a raised mucous membrane manifesting as a type of papillae. Filiform papillae were differentiated into two subtypes: brush-like papillae, with a short base splitting into 5-6 processes; and flower bud filiform papillae that are shorter and wider than the former, and divided into a single main process and 4-5 secondary processes. Fungiform papillae with 1-2 taste buds are interspersed between filiform papillae and absent on the radix. Conical papillae cover the lateral margin of the corpus and increase in size when closer to the radix. Vallate papillae-three in number-are arranged as a triangular structure, with the middle papillae pointing towards the root of the tongue. A continuous groove wrapped around each papilla with several taste buds is found on its lateral surface. Two of the vallate papillae are located symmetrically on each side and are much smaller than the most caudal middle vallate that is directed posteriorly. A positive reaction using separate staining with periodic acid-Schiff and Alcian blue (pH 2.5) showed Weber's glands and von Ebner's glands appearing beneath the papillae, mainly on the muscle layer of the radix. Different reactions to the stains indicated that Weber's gland contains sialomucin and/or sulfomucin, whereas von Ebner's gland consists of serous cells secreting glycogen and/or neutral mucin. The collagen structure was identified using Masson's trichrome stain in the two bottom layers of the tongue from the apex, decreasing gradually towards the radix.

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.

Ultrastructural features on the oral cavity floor (tongue, sublingual caruncle) of the Egyptian water buffalo (Bubalus bubalis): gross, histology and scanning electron microscope

The present work was focused on the morphological characters of the lingual caruncles, and tongue with its papillae of Egyptian water buffalo (Bubalus bubalis) using the gross, light, and scanning electron microscope. The ventral surface of the sublingual caruncle carried a small opening of the duct of both monostoamtic and mandibular salivary gland. The lingual mucosa of dorsal, lateral border, some extent to ventral surface of apex had lingual papillae (filiform, fungiform), while the lingual mucosa of body especially at torus linguae had conical papillae, but circumvallate papillae observed at the caudal part of body and root. The dorsal surface of apex and body carried numerous long thread-like with blunt apex caudally directed filiform papillae that covered with keratinized scales without secondary papillae. The degree of keratinization classified filiform papillae into rostral part of high keratinization and caudal less keratinization. Conical papillary surface carried exfoliated epithelium with longitudinal groove on its rostral surface and had CT core does not reach the level surface of epithelium and carried secondary papillae. Fungiform papillae scattered among filiform papillae on the dorsal and ventral surface of apex and its convex surface had exfoliated keratinized epithelium. Circumvallate papillae surrounded by circular deep groove that bordered by vallum that carried small secondary papillae that ended into the primary groove. Taste buds of circumvallate papillae opened in the lateral lining epithelium facing the groove. Von Ebner's glands were observed in CT under papillae especially toward the groove and their ducts open into the base of the groove.

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.

Structural and Functional adaptation of the lingual papillae of the Egyptian fruit bat (Rousettus aegyptiacus): Specific Adaptive feeding Strategies

The current investigation was directed to clarify the correlations between the feeding strategy and lingual structure of the Egyptian fruit bat captured from the Egyptian east desert. The current work depends on twelve adult Egyptian fruit bats that observed grossly and with the help of the stereo, light, and scanning electron microscope. There were three types of the lingual papillae; one mechanical filiform and two gustatory (fungiform and circumvallate). There were seven subtypes of filiform papillae were recognized on the seven lingual regions. There were scanty numbers of fungiform papillae distributed among the filiform papillae on the lingual tip and two lateral parts of apex and body while fungiform papillae completely absent in the median part. There were three circumvallate papillae. The central bulb of circumvallate papillae surrounded by one layer of two segmented circular annular bad. The lingual tip had cornflower-like and diamond-shaped filiform papillae. Histochemical results revealed that the lingual glands were a stronger AB-positive reaction and gave dark blue color, while the reaction for the PAS-stain was negative. Also, the glands exhibited a blue color as an indication of positive AB reactivity with combined AB-PAS staining.

Morphogenesis of the New Zealand white rabbit tongue (Oryctolagus cuniculus)

The current study was designed to describe the prenatal developmental stages of the rabbit tongue. Thirty-five embryos of prenatal ages (E16, E19, E23, E25, E28, and Postnatal) were obtained from New Zealand white (NZW) rabbit. The primordia of the tongue were observed on the foundation as early as day 16 prenatal age (E16). The first primordia of lingual papillae were observed that including the primordia of circumvallate papillae at day 19 prenatal (E19). Thickenings of lingual epithelium developed at 19 day prenatal of embryo. At day 23-25 pc, the presence of primordia of foliate papillae was shown in addition to primordia of the fungiform and filiform papillae were found. The development of the final shape of the tongue is a longstanding process that occurs during the prenatal and postnatal life. The first primordia of gustatory papillae appear, and only later primordia of mechanical papillae are formed. In conclusion, the morphogenesis of the tongue and its lingual papillae discussed its herbivorous nature of feeding.

Morphological and scanning electron microscopic studies of the lingual papillae of the tongue of the goat (Capra hircus)

The morphology of different lingual papillae of the Egyptian goats was studied by gross observation, scanning electron microscopy, and light microscopy. According to function, two types of papillae were present; mechanical (filiform, conical and lenticular papillae) and gustatory papillae (fungiform and vallate papillae). Two types of filiform papillae were detected with different shape and position. Moreover, two types of conical and lenticular papillae could be recognized on the lingual torus. Abundant fungiform papillae were found on the dorsal and ventral surfaces of the tip of the tongue. The vallate papillae had also different shapes. Taste buds were demonstrated within the epithelium of the dorsal surfaces of the fungiform papillae and the lateral surfaces of the vallate papillae. In addition, a longitudinal row of large papillae was located on the lateral aspect of the tongue in relation to the filiform papillae. These papillae were suggested to be called elongated conical papillae and may be considered as ones of the lingual papillae. In conclusion, the current study provides a detailed description of the different lingual papillae of the Egyptian goat's tongue. Presence of different types and shapes of mechanical and gustatory lingual papillae in goats' tongue suggests a high degree of functional adaptation to their diet.

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.

Macro- and microscopic study on the tongue and lingual papillae of Bison bonasus hybrid as an interspecific species (Bos taurus × Bison bonasus)

Nowadays the processes of crossing of different mammalian species are well characterized in light of genetics, and possibility of reproduction. Generally, lack detailed studies on changes in anatomy and histology of internal systems of hybrids. Bison bonasus hybrid is an interspecific species between the bull of European bison (Bison bonasus), and female of domesticated cattle (Bos taurus). To study the anatomy of tongue and distribution of lingual papillae on Bison bonasus hybrid tongue, a stereomicroscopic and scanning electron microscopic observations was conducted. We aimed to study the appearance of macro- and microscopic traits in relation to parental species and other bovids. Results indicate that Bison bonasus hybrid tongue possesses characteristic traits for parental species and ruminants from Bovidae family and also species-specific features differ from mentioned animals. Specific new traits in hybrid are: V-shaped arrangement of lingual papillae on ventral surface of the tongue, rosette arrangement of conical papillae on the top of lingual prominence, bigger number of vallate papillae and closer arrangement of vallate papillae. In hybrid observed also the appearance of combination of parental traits. Similar to European bison are rectangular shape of lingual prominence and absence of filiform papillae on the root of tongue. Presence of lateral processes of filiform papillae on the apex of tongue, and arrangement of vallate papillae into two rows corresponded to cattle. Development of new morphological features of tongue and its mucosal papillae in Bison bonasus hybrid opens new issue for future studies on organs of digestive system in animals after hybridization.

Morphological and scanning electron microscopic study of the lingual papillae in the Javan Pipistrelle (Pipistrellus javanicus)

There are vast numbers of bats, in terms of both individuals and species, in Indonesia, although the precise species count is currently unknown. These bats demonstrate great variation in feeding patterns, with some being insectivorous, frugivorous, nectar-eating or carnivorous. One of the insectivorous bats found on Java Island, Indonesia, is the Javan pipistrelle (Pipistrellus javanicus). This paper presents a detailed morphological description of the tongue and lingual papillae of P. javanicus, using scanning electron microscopy (SEM) and light microscopy (LM). Macroscopically, the elongated tongue of P. javanicus can be divided into three sections: the apex, corpus and radix. On the dorsal part of the tongue (corpus), there is a prominence called the mediodorsal lobe, the lobe begin from the end of apex. On the radix, in the medial part, we describe the presence of a sulcus medianus. The SEM and LM observations show that the apex of the tongue bears three types of papillae: crown filiform, pronged filiform and fungiform. The corpus bears conical and fungiform papillae, whereas the radix bears vallate, large filiform, small filiform and fungiform papillae. Taken together, these results contribute to research on the tongue anatomy and feeding habits of the bat.

Morphology of the lingual papillae of the bharal (Pseudois nayaur)

We examined the dorsal lingual surfaces of an adult bharal (Pseudois nayaur) by scanning electron microscopy. The filiform papillae of the lingual apex and body consisted of a main papilla and smaller secondary papillae. The filiform papilla of the lingual body was big as compared to that of the lingual apex. The connective tissue cores of the filiform papillae consisted of several processes. The fungiform papilla was round in shape. The connective tissue cores of the fungiform papillae were flower-bud shaped. The lenticular papillae of large size were limited on the lingual prominence. The connective tissue cores of the lenticular papillae were hair-like in shape. The vallate papillae were located on both sides of the posterolateral aspects. The vallate papillae were flattened-oval shaped and the papillae were surrounded by an oval-shaped trench. The connective tissue cores of the vallate papillae were covered with numerous small spines The lingual surface of the bharal closely resembled that of the family Bovidae.

Morphological study of the lingual papillae in the fruit bat (Rousettus amplexicaudatus) by scanning electron microscopy and light microscopy

This study was carried on the tongues of ten normal, healthy and adult fruit bats (Rousettus amplexicaudatus, also known as the nyap biasa bat) in Yogyakarta, Java Island, Indonesia. The tongue was protrusible, elongated and flat with a rounded apex, and its width and thickness increased gradually towards to lingual root. There were two main types of lingual papillae, mechanical (filiform) and gustatory (fungiform and circumvallate). The tongue was divided into three parts (apex, corpus and radix), and then, each part was subdivided into three regions (two lateral regions and a median region). There were six subtypes of the filiform papillae-three types on the anterior part (small, scale-like and giant), one type on the middle part (leaf-like papillae) and two types on the posterior part (rosette-shaped filiform and conical filiform papillae)-in addition to transitional papillae presented on the corpus and radix. Two types of gustatory papillae were represented by a small number of fungiform papillae that are scattered among the filiform papillae on the lingual apex and corpus, while three circumvallate papillae on the posterior part are arranged in a "V" shape pointing directly at the larynx.

Surface ultrastructural descriptions of the oropharyngeal cavity of Anas querquedula

The current work considers the first anatomical description of oropharyngeal cavity of Garganey, which was performed on eight heads with the help of scanning electron microscopy (SEM). The round apex of elongated tongue has anterior spatula-like named lingual nail. SEM of dorsal surface of lingual nail carry microtubercles and micropores on its rostral part, while its caudal part carry numerous microridges and micropores, while lateral apical surface only without lingual nail carrying filiform papillae, but its ventral surface carry exfoliated scales-like projections. Lateral lingual tip carries numerous laterally directed hairs-like structures. Rostral part of body carry region of small conical papillae in between them small hairs-like papillae on its lateral surface. Middle part of body carry lingual comb on its dorsal surface, while its lateral surfaces carry region of small conical papillae in between them hairs-like papillae in addition to filiform papillae, and large conical with small filiform papillae begin to appear laterally to the heads of lingual comb. Lateral surface of lingual prominence carry region of large conical and small filiform papillae on its rostral part, while its caudal part occupied by laterally situated spinated border from the root. Lingual root has two triangular smooth middle and spinated lateral and caudal. Laryngeal entrance divided into papillary and nonpapillary regions. Roof of oropharyngeal cavity divided into lamellar and papillary regions. Choanal cleft divided into rostral narrow ¼ and wide caudal ¾ parts. In conclusion, feeding process depend on the filter feeding mechanism that performed by the help of lateral situated papillae with lingual prominence.

Morphology of the Lingual Papillae of the Japanese lesser flying squirrel and four-toed hedgehog

Author examined the dorsal lingual surfaces of the adult Japanese lesser flying squirrel (Pteromys momonga) and four-toed hedgehog (Atelerix albiventris) by scanning electron microscopy. In the Japanese lesser flying squirrel, the filiform papilla of the lingual body consisted of a large conical papilla. The filiform papilla of the lingual prominence was spoon in shape. The fungiform papillae were round in shape and scattered among the filiform papillae. Many foliate papillae were observed on the posterolateral regions of the lingual body. The foliate papillae had some ridges separated by deep grooves. The vallate papilla was located between lingual body and root. Several long conical papillae derived from the posterolateral margin of the tongue. In the four-toed hedgehog, the filiform papilla of the lingual apex had a conical process. The filiform papilla of the lingual body had some processes. The fungiform papillae were round in shape. The foliate papillae were observed on the posterolateral regions of the lingual body. The papilla was separated from each other by a furrow. The vallate papilla consisted of a central papilla and an annular pad. These findings suggest that in the structure of the lingual papillae of the Japanese lesser flying squirrel there is similar to that of the sugar glider and the lingual papillae of the four-toed hedgehog is different from that of the Japanese lesser flying squirrel.

Morphology of the lingual papillae in the leopard

We microscopically examined the dorsal lingual surface of an old leopard (Panthera pardus). The filiform papillae on the lingual apex were dome-shaped. The connective tissue cores of the filiform papillae resembled a well in shape, while those of the fungiform papillae were not hollow. The filiform papillae on the anterior part of the lingual body were large and cylindrical in shape. The connective tissue cores of these filiform papillae consisted of large conical papillae. The filiform papillae on the central part of the lingual body were large and conical-shaped. The connective tissue cores of the filiform papillae consisted of a large main process. The vallate papillae were surrounded by grooves. The top of the connective tissue core of the vallate papilla had many ditches. These findings are peculiar to the tongue of members of the family Felidae.

Morphology of the lingual papillae in the Asian golden cat

We microscopically examined the dorsal lingual surface of an adult Asian golden cat (Catopuma temminckii). The papillae on the margin of the lingual apex were horny-shaped and fungiform. The filiform papillae on the anterior part of the lingual body were large and cylindrical; the connective tissue core of each of these comprised a large conical papilla. The filiform papillae on the central part of the lingual body were large and conical-shaped on the medial side and dome-shaped on the lateral side. The connective tissue core of each medial filiform papilla comprised a large main process and some secondary processes, while processes were absent on the lateral side. These findings are peculiar to the tongue of members of the family Felidae.

Comparative Morphology of the Lingual Papillae and Their Connective Tissue Cores in the Tongue of Pallas's Squirrel (Callosciurus erythraeus thai, Kloss, 1917)

We observed the morphology of the papilla linguae (filiform, fungiform, foliate, and vallate) and underlying connective tissue cores (CTCs) in Pallas's squirrel (Callosciurus erythraeus thai) using light and scanning electron microscopy. The tongue was caudally elongated and lacked the lingual torus. Filiform papillae were densely distributed along the dorsal surface of the apex, and the rostral and caudal parts of the corpus, but were attenuated in the lingual root. Two or three vallate papillae that were rounded or elongated were situated at the boundary between the caudal part of the corpus and lingual root, and foliate papillae and associated cone-like processes were observable in the lateral margin of the caudal end. The epithelial surface of filiform papillae had a main process and a few associated processes that varied between short and elongated, depending on the location. Filiform papillae CTCs appeared to have a few processes that caudally surrounded a concavity and were morphologically variable based on location. Moreover, fungiform papillae CTCs appeared to be columnar cores and had a shallow convex curve at the top. The Pallas's squirrel's tongue exhibited transitional morphological characteristics between Rodentia and other mammalian species, in that they lacked the lingual torus and had CTCs of lingual papillae that were somewhat morphologically similar to those of other non-Glires species, especially treeshrews and tamarins, rather than those of other Rodentia species.

Light and scanning electron microscopy of the tongue of the sand lizard (Lacerta agilis)

BACKGROUND

Despite the fact that numerous reptile species are widely studied by the researchers, information describing the detailed structure of particular organs in many reptiles is missing.

MATERIALS AND METHODS

The tongue of the sand lizard (Lacerta agilis) was examined under the light and scanning electron microscope. It is divided into bifurcated apex, corpus and bifurcated radix. The tip of the lingual apex is devoid of lingual papillae.

RESULTS

The remaining dorsal surface of the tongue bears either fused papillae in the form of caudally directed ridges or individual papillae represented by mu- shroom-like or semilunar prominences (lingual apex) or fish scale-like papillae (lingual corpus) and horizontally laid ridges extending in the form of lobulated prominences (lingual corpus, lingual radix). Regardless of the shape, lingual papillae contain numerous muscle fibres and they are all considered to be mechanical. The lingual epithelium changes from the simple squamous into stratified squamous in the caudal direction. No salivary glands or sensory structures were recognised.

CONCLUSIONS

This description is to be used mainly for comparative studies. It could also help to understand how different lizards capture the pray.

Morphology of the lingual papillae of the lion-tailed macaque

We microscopically examined the dorsal lingual surface of an adult lion-tailed macaque (Macaca silenus). The tongue of the chimpanzee was about 13 cm long. Filiform papillae on the lingual apex consisted of several pointed processes. There were dome-shaped fungiform papillae scattered among the filiform papillae. The connective tissue cores of those filiform papillae consisted of processes of various size, while these of the fungiform papillae had several ditches. The vallate papilla was surrounded by a groove and pad, and were flattened-oval shaped. The connective tissue cores of the vallate papillae were covered with numerous small spines. Many foliate papillae were observed on the posterolateral regions of the tongue. After removing epithelium from the foliate papillae many processes became apparent.

Morphology of the lingual papillae of the Chapman's zebra (Equus quagga chapmani)

We examined the dorsal lingual surfaces of an adult Chapman's zebra by scanning electron microscopy. The filiform papillae of the lingual apex consisted of a main papilla and smaller secondary papillae. The fungiform papillae were round in shape. The filiform papillae of central region of the lingual body were needle-like in shape. The filiform papillae of posterior region of the lingual body were hair-like in shape. Many grooves were observed on posterolateral regions and the fungiform papillae were observed on the inside of some grooves. The vallate papillae were located on both sides of the posterior region and surrounded by a groove. The anatomical characteristic of the lingual surface of the Chapman's zebra is the fungiform papillae on the inside of some grooves.

Morphology of the lingual papillae of the polar bear (Ursus maritimus)

We examined the dorsal lingual surfaces of a newborn and an old polar bears by using scanning electron microscopy. In the newborn polar bear, the filiform papilla on the lingual apex was cylindrical in shape. The connective tissue core of the filiform papillae was needle-shaped and that of the fungiform papillae was funnel-shaped. The filiform papillae on the lingual body was dome-shaped. The connective tissue core of the filiform papillae was U-shaped and that of the fungiform papillae was column-shaped. On the lingual apex and body, there could not distinguish the filiform from fungiform papillae. The connective tissue core of the filiform papilla was different from the fungiform papilla. The vallate papillae were surrounded by a groove and pad and the surface was smooth. In the old bear, the filiform papilla on the lingual apex had several pointed processes. The processes of the filiform papilla on the lingual body were larger than those of the lingual apex. The vallate papillae were surrounded by a groove and pad and the surface was rough. There are no foliate papillae.

Morphology of the lingual papillae in the chimpanzee

We microscopically examined the dorsal lingual surface of an adult chimpanzee (Pan troglodytes). The tongue of the chimpanzee was about 13 cm long. Filiform papillae were distributed over the entire dorsal surface of the lingual body. There were many fungiform papillae scattered among the filiform papillae. At the posterior end of the lingual body, a triangular arrangement of the vallate papillae, with the apex of the triangle directed posteriorly, was observed. The filiform papillae on the lingual apex consisted of a main papilla and secondary papillae. The filiform papillae on the lingual body had several pointed processes. There were dome-shaped fungiform papillae scattered among the filiform papillae. The vallate papillae were surrounded by grooves and were flattened-oval shaped. Many foliate papillae were observed on the posterolateral regions of the tongue.

Structural and ultrastructural features of the agouti tongue (Dasyprocta aguti Linnaeus, 1766)

The agouti (Dasyprocta aguti Linnaeus, 1766) is a wild rodent belonging to the family Dasyproctidae that is found throughout Brazil and feeds on fruits and seeds. The aim of the present study was to describe the following features of the tongue of agouti: its morphological structures, the three-dimensional characteristics of the lingual papillae surface, the connective tissue cores (CTCs) and the epithelial cell ultrastructure. Four types of papillae were observed on the dorsal surface of the tongue with a triangular shape: filiform, fungiform, foliate and vallate. Filiform papillae were distributed throughout the tongue surface, and removal of the epithelial surface revealed conical CTCs and multifilaments. Fungiform papillae were observed in the rostral and middle regions, whereas foliate papillae developed in pairs on the lateral margin of the caudal region. Removal of the epithelium in these regions revealed CTCs with parallel laminar conformation. Vallate papillae were arranged in a V-shape in the caudal region, and their CTCs ranged in shape from elongate to ovoid. The ultrastructural components of the dorsal epithelium were the basal, spinous, granular and keratinised layers. A broad area with cytoplasmic projections was identified in the interface region between the lamina propria and the basal layer. Flattened cells with intermediate filaments were observed in the transitional region between spinous and granular layers. The keratinised layer was composed of superimposed epithelial cells where desmosomes and cell-surface microridges were observed. These structural features, including the three-dimensional aspects of the lingual papillae, the CTCs and the epithelial ultrastructure, indicate that when compared with other animals, particularly other rodent species, the morphological features of the tongue of agouti are relatively well developed, especially regarding foliate and vallate papillae.

Specialized bat tongue is a hemodynamic nectar mop

Nectarivorous birds and bats have evolved highly specialized tongues to gather nectar from flowers. Here, we show that a nectar-feeding bat, Glossophaga soricina, uses dynamic erectile papillae to collect nectar. In G. soricina, the tip of the tongue is covered with long filamentous papillae and resembles a brush or mop. During nectar feeding, blood vessels within the tongue tip become engorged with blood and the papillae become erect. Tumescence and papilla erection persist throughout tongue retraction, and nectar, trapped between the rows of erect papillae, is carried into the mouth. The tongue tip does not increase in overall volume as it elongates, suggesting that muscle contraction against the tongue's fixed volume (i.e., a muscular hydrostat) is primarily responsible for tip elongation, whereas papilla erection is a hydraulic process driven by blood flow. The hydraulic system is embedded within the muscular hydrostat, and, thus, intrinsic muscle contraction may simultaneously increase the length of the tongue and displace blood into the tip. The tongue of G. soricina, together with the tongues of nectar-feeding bees and hummingbirds, which also have dynamic surfaces, could serve as valuable models for developing miniature surgical robots that are both protrusible and have highly dynamic surface configurations.

NTPDase2+ Cells Generate Lingual Epithelia and Papillae

The tongue epithelium is one of the most rapidly self-renewing tissues in adult mammals. Multiple stem cell populations are currently believed to exist in tongue epithelia. Keratin 14 (K14) positive cells differentiate into either lingual epithelia or lingual papillae, while ecto-nucleoside triphosphate diphosphohydrolase 2 (NTPDase2) is associated with neural stem cells and astrocyte-like cells ensheathing the migrating neuroblasts. Here, using a transgenic mouse expressing rtTA from the mouse NTPDase2 promoter, we generated an inducible model by treatment with Doxycycline. By immunohistochemical analysis and in situ hybridization, we found exclusive expression of NTPDase2 in lingual epithelia and lingual papillae. Using inducible genetic cell fate mapping, we further showed that the NTPDase2+ cells generated lingual papillae and epithelia in the adult tongue. Finally, building on our previously proposed paradigm of cell migration stream, a model is further described here for lingual epithelia cell genesis. In short, the current results not only extend our understanding of the cell migration stream in lingual epithelia and lingual papillae, but they also support the concept of multiple stem cell populations in lingual epithelia and papillae.

Functional morphology of the tongue in the domestic goose (Anser anser f. domestica)

Using LM and SEM methods, the study describes microstructures in particular areas of the tongue of the goose. A thick multilayered keratinized epithelium forms the "lingual nail" and covers small and giant conical papillae, whereby the first functions as an exoskeleton of the tongue apex, and the latter are arranged along the lingual and well-developed connective tissue cores, and together with the bill lamellae are involved in cutting. The row of conical papillae on the lingual prominence prevents regurgitation of transported food. In the area of the "lingual nail" and in the anterior part of the lingual prominence, Herbst corpuscles are accumulated, which allow to recognize food position. Filiform papillae, as widely distributed between the conical papillae of the body, are responsible for filtering. They can be explained as long keratinized processes of the epithelium and are devoid of connective tissue cores. During food transport, the flattened areas of the lingual body and the lingual prominence are protected by a parakeratinized epithelium, but the root is covered by a nonkeratinized epithelium. The presence of adipose tissue in the tongue probably reduces pressure during food passage, but also promotes mucus evacuation from the lingual glands, thus facilitating food transport. An entoglossal bone with a continuation as cartilage is the stable structural basis of the tongue system.