Scanning electron microscopic study on the tongue and lingual papillae of the adult Spotted seal, Phoca largha

We observed the external surface and connective tissue cores (CTCs) of the lingual papillae (filiform, fungiform and vallate papillae) of adult Spotted seals (Phoca largha) using SEM and light microscopy. The tongue was V-shaped and its apex was rather rounded. On the dorsal surface from apex to the one-third posterior of the tongue, the lingual mucosa was densely covered by filiform papillae, with a scatted distribution of dome-like fungiform papillae, which have orthokeratinized epithelium. At the posterior part of the tongue, filiform papillae were totally diminished and their epithelium was parakeratinized. Approximately 6-7 vallate papillae were arranged in a V-shape on the posterior of the tongue. After removal of the epithelium, the CTCs of the filiform papillae that were distributed at apex consisted of a primary core and approximately 5-6 rod-shaped small accessory cores. The CTCs of filiform papillae that were distributed at anterior part of the tongue lacked primary protrusions and possessed approximately 10-15 rod shaped small accessory cores that were arranged in a horseshoe manner. The CTCs offungiform papillae had cylindrical primary cores and were fringed with accessory protrusion. In the Vallate papillae, taste buds were only seen at the dorsal epithelium.     

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

We observed the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform, foliate and vallate papillae) of the common raccoon (Procyon lotor) using scanning electron microscopy and light microscopy. The tongue was elongated and their two-third width was almost fixed. Numerous filiform papillae were distributed along the anterior two-thirds of the tongue and fungiform papillae were distributed between the filiform papillae. Eight vallate papillae that had a weak circumferential ridge were distributed in a V-shape in the posterior part of the tongue and numerous taste buds were observable in the circumferential furrows of vallate papillae. Weak fold-like foliate papillae were observable at the lateral edge in the posterior part of the tongue and a few salivary duct orifices were observable beneath the foliate papillae. An islet-like structure with numerous taste buds, was observable on the deep part of the salivary duct of foliate papillae. Large conical papillae were distributed at the posterior part and root of the tongue. After removal of epithelium, filiform papillae of CTCs were appeared to be a thumb or cone-like main core and associating several finger-like short accessory cores. These cores were surrounded an oval concavity. The main core was situated behind the concavity and associated with accessory cores. CTCs of fungiform papillae were cylinder-like with numerous vertically running ridges and with a few concavities seen at the top of the cores. CTCs of vallate papillae and their surrounded circumferential ridge were covered with numerous pimple-like protrusions. The lingual papillae of Common raccoon's tongue had morphological feature of carnivore species.     

Light and scanning electron microscopic study on the lingual papillae and their connective tissue cores of the Cape hyrax Procavia capensis

We examined the epithelial surface and connective tissue cores (CTCs) of each lingual papilla on the Paenungulata, Cape hyrax (Procavia capensis), by scanning electron microscopy and light microscopy. The tongue consisted of a lingual apex, lingual body and lingual root. Filiform, fungiform and foliate papillae were observed on the dorsal surface of the tongue; however, fungiform papillae were quite diminished on the lingual prominence. Moreover, no clearly distinguishable vallate papillae were found on the tongue. Instead of vallate papillae, numerous dome-like large fungiform papillae were arranged in a row just in front of the rather large foliate papillae. Foliate papillae were situated in the one-third postero-lateral margin of the lingual body. The epithelium of filiform papillae was covered by a keratinized layer with kerato-hyaline granules, whereas weak keratinization was observed on the interpapillary epithelium. The external surface of the filiform papillae was conical in shape. CTCs of the filiform papillae were seen as a hood-like core with a semicircular concavity in the anterior portion of each core. Large filiform papillae were distributed on the lingual prominence. The CTCs of large filiform papillae after exfoliation of their epithelium consisted of a concave primary core and were associated with several small protrusions. The surface of fungiform papillae was smooth and dome-like. After removal of the epithelium, CTCs appeared as a flower bud-like primary core and were associated with several protrusions that were arranged on the rim of the primary core. Several taste buds were found on the top of the dorsal part of the epithelium of both fungiform and large fungiform papillae. Well-developed foliate papillae were seen and numerous taste buds could be observed in the lateral wall of the epithelium in a slit-like groove. The morphological characteristics of the tongue of the Cape hyrax had similarities with other Paenungulata such as Sirenia. However, three-dimensional characteristics, especially CTCs of lingual papillae, exhibited multiple similarities with rodents, insectivores and artiodactyls.     

Comparative morphological study on the lingual papillae and their connective tissue cores (CTC) in reeves’ muntjac deer (Muntiacus reevesi)

The lingual papillae and their connective tissue cores (CTC) from Reeves’ muntjac deers (herbivorous artiodactyla) were studied using light and scanning electron microscopy and then compared to those of other mammalian species. At the posterior portion of the tongue, the Reeves’ muntjac has a lingual prominence on which large conical papillae are distributed. On the dorsal surface of the anterior tongue, numerous filiform papillae were found. Externally, each filiform papilla consists of a rod-shaped main process and several small accessory processes. Their CTCs consist of 10 or more rod-shaped processes arranged in a horseshoe pattern and several posterior processes forming a small circular pattern. This structure is a common characteristic of artiodactyla, through which Reeves’ muntjac deer can be categorized in a position in the artiodactyla class lying between the bighorn sheep and the East African bongo. Fungiform papillae are distributed among the filiform papillae on the anterior portion of the tongue. Large fungiform papillae are also sparsely distributed on the lingual prominence and have several taste buds in the epithelium on the surface. Ten or more vallate papillae are distributed at the postero-lateral area of the lingual prominence and numerous taste buds are distributed in the epithelium of their side.     

Comparative morphological study on the stereo-structure of the lingual papillae and their connective tissue cores of the American beaver (Castor canadensis)

The lingual papillae and the connective tissue cores (CTC) of the American beaver were examined by light and scanning electron microscopy. The tongue of American beaver was about 9 cm in length, 3.5 cm in width, and has a lingual prominence. Four types of papillae (filiform, fungiform, vallate and foliate papillae) were observed. The filiform papillae can be classified into three types (filiform, large filiform and dorm-like papillae). Filiform papillae distributed on the anterior tongue and posterior of the lingual prominence consisted of a posterior thick main process and several small accessory processes. After removal of the epithelium, the CTCs of the filiform papillae had U-shaped, horseshoe-like primary cores with 10-15 rod-shaped small accessory cores. Large filiform papillae were distributed at the anterior margin of the lingual prominence. Dome-like papillae were distributed at the top of lingual prominence. Fungiform papillae were observed two types. Fungiform papillae, which were distributed at the anterior tongue, were round shaped. Fungiform papillae of the posterior of the lingual prominence were large and surrounded with a papillary groove. At the posterior of the tongue, three vallate papillae were arranged in a triangular pattern. Foliate papillae were on 22 to 25 parallel ridges and grooves.     

Morphology of the dorsal lingual papillae in the bush dog (Speothos venaticus)

The dorsal lingual surface of a bush dog (Speothos venaticus) was examined by scanning electron microscopy (SEM). The tongue was about 7 cm in length. Filiform, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. Each filiform papillae on the apical surface of the tongue had several conical processes, in the midportion were larger than those on the apex in size. In the region of the vallate papillae, the filiform papillae had not the conical processes and more larger than those on the midportion of the tongue. The fungiform papillae were present rounded bodies and more densely distributed on the tip of the lingual apex. There were 5 vallate papillae on both sides. The vallate papillae were located on both sides of the posterior end of the lingual body. Each papilla was surrounded by a groove and a crescent pad. In the dorsal surfaces of the papillae, small conical papillae were observed.     

Morphological characteristics of the tongue and lingual papillae of the large bamboo rat (<Emphasis Type="Italic">Rhizomys sumatrensis</Emphasis>)

The large bamboo rat (Rhizomys sumatrensis) is a fossorial rodent found throughout Indochina that has a distinct habitat dominated by bamboo thickets. In the study reported here, the lingual biology of this rodent is described in detail, based on characteristic features of the tongue and lingual papillae as determined by light and scanning electron microscopy studies. The tongue was found to be elongated with a rounded apex and possessed a median groove and a well-developed intermolar prominence. Three types of the papillae were found on the dorsal lingual surface: filiform, fungiform and vallate papillae. The most abundant papillae were the filiform papillae, the majority of which had a wide base and fork-like processes. Rounded fungiform papillae with one to four taste buds were randomly distributed among the filiform papillae, with a high density found at the anterior tongue, particularly the apex. Two oval vallate papillae were observed on the posterior part of the tongue, surrounded by a circumferential groove into which their numerous gustatory pores opened. The lingual radix had no papillae but contained mucus-secreting Weber’s salivary glands. Structural adaptations of the tongue to meet the functional demands of food ingestion and food manipulation in the oral cavity are also discussed.     

Morphology of the lingual papillae in the raccoon dog and fox

The dorsal lingual surfaces of the raccoon dogs (Nyctereutes procyonoides) and fox (Vulpes vulpes japonica) were examined by scanning electron microscopical (SEM) observations. The distribution and type of the lingual papillae found in the raccoon dog were similar to those in the fox. Filiform, fungiform, foliate and vallate papillae were observed. The filiform papillae were distributed over the entire dosal surface of the tongue. Each filiform papilla on the apical surface of the tongue had several pointed processes. The filiform papillae of the lingual body consisted of a main papilla and some secondary papillae. The fungiform papillae were present rounded bodies, and more densely distributed on the lingual apex. The foliate papillae were seen on the dorsolateral aspect of the tongue. The vallate papillae were located on both sides of the posterior end of the lingual body. Each papilla was surrounded by groove and crescent pad. On the periphery of the papillae, large conical papillae were observed.     

Light and Scanning Electron Microscopic Study on the Tongue and Lingual Papillae of the Common Hippopotamus,Hippopotamus amphibius amphibius

We observed the three‐dimensional structures of the external surface and connective tissue cores CTCs, after exfoliation of the epithelium of the lingual papillae (filiform, fungiform, and foliate papillae) of the common hippopotamus (Hippopotamus amphibius amphibius) using scanning electron microscopy and conventional light microscopy. Following unique features were found; typical vallate papillae with a circumferential furrow were not observable. Instead, numerous large fungiform papillae were rather densely distributed on the posterior of the lingual prominence. Taste buds were observable only on the dorsal epithelium. Serous lingual gland was not seen in the lamina propria; however, mucous‐rich mixed lingual glands were found and in a few of orifices were seen on the large fungiform tops. Lingual prominence was diminished their width. Rather long and slender conical papillae were distributed on the lingual prominence and were similar to nonruminant herbivore, that is donkey. Beside this narrow lingual prominence, lateral slopes were situated with numerous short spine‐like protrusions. After removal of the epithelium, CTCs of lateral slopes exhibited attenuated flower bud structures. Large‐conical papillae were situated on the root of the tongue. These large conical papillae were not seen among ruminants and seen on the lingual root of omnivores and carnivores. It implies that lingual structure of common hippopotamus possessed mixed characteristics between Perissodactyls, Ruminantia, and nonherbivores such as Suiformes because of their unique evolutionally taxonomic position. Moreover, adaptation for soft grass diet and associating easier mastication may be also affecting these mixed morphological features of the tongue. Anat Rec, 292:921–934, 2009. © 2009 Wiley‐Liss, Inc.     

Morphology of the lingual papillae in the tiger

The dorsal lingual surfaces of an adult tiger (Panthera tigris altaica) was examined by macroscopical and scanning electron microscopical observations. Filiform, fungiform and vallate papillae were observed. The filiform papillae were distributed over the entire dosal surface of the tongue. The fungiform papillae were present rounded bodies, and more densely distributed on the lingual apex. There were 4 vallate papillae in total on borderline between the lingual body and lingual radix. Each papilla was surrounded by a groove. No foliate papillae were seen on the dorsal surface. Openings of the glandular ducts on the regions of the vallate papillae were found.     

Morphology of the dorsal lingual papillae in the barbary sheep, Ammotragus lervia

The dorsal lingual surface of a barbary sheep (Ammotragus lervia) was examined by scanning electron microscopy (SEM). The tongue was about 20 cm in length. There were about 30 vallate papillae on both sides. Filiform, conical, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue, excepted for the lingual torus where conical papillae were present. The fungiform papillae were present rounded bodies, and more densely distributed as compared to that of the lingual body on the tip and ventral surface of lingual apex. No foliate papillae were seen on the dorsal surface. The vallate papillae were located on both sides of the midline in the caudal part. Each papilla was surrounded by a groove. These findings indicate that the tongue of the barbary sheep is similar to that of the formosan serow, japanese serow and blackbuck.     

Stereo architecture of the connective tissue cores of the lingual papillae in the treeshrew (Tupaia glis).

Summary The stereo architecture of the lingual connective tissue cores (CTC) in the treeshrew (Tupaia glis) (which has the primitive characteristics of primates) was observed by scanning electron microscopy, and compared to that of other animal orders. The tongue of the treeshrew has three vallate papillae which are situated in the posterior part of the tongue, while some macaques have several vallate papillae. Among numerous filiform papillae, fungiform papillae are sporadically distributed. A filiform papilla consists of a bundle of several slender spine-like processes arranged in a circle at the basal margin. After removal of the epithelium, the CTC of the filiform papilla looks like a human hand raised with the palm facing towards the tongue tip. The fungiform CTC in the threeshrew is columnar in shape (rather similar to that of Insectivora and Rodentia) and at the top there are several round depressions for taste buds. In the treeshrew several large rod-shaped processes are derived from the postero-lateral margin of the tongue, as in Carnivora (dogs and cats), where foliate papillae are located in many other animal species. The treeshrew has numerous characteristics similar to those of the crab-eating macaque (Primates), but at the same time it has some characteristics similar to those of Insectivora, Rodentia, Carnivora and Artiodactyla.     

Light and Scanning Electron Microscopic Study on the Structure of the Lingual Papillae of the Feathertail Glider (Acrobates pygmeus,Burramyidae, Marsupialia)

The structure of the tongue of the marsupial feathertail glider (Acrobates pygmeus) was observed under a light and scanning electron microscope. The elongated tongue with a sharpened apex is ca. 10 mm in length. Only the posterior half of the tongue is attached to the bottom of the oral cavity by the frenulum, which facilitates considerable mobility of the anterior free part of the tongue. On the dorsal surface of the tongue, three types of lingual papillae were distinguished, that is, mechanical filiform papillae and gustatory fungiform and vallate papillae. The arrangement, shape, and size of filiform papillae and the direction of their keratinized processes change depending on the part of the tongue, so that the surface of the apex and the body of the tongue resembles a brush adapted to effective holding of semiliquid food and collection of pollen. The fungiform papillae have a single taste bud and are uniformly scattered between filiform papillae only on the anterior half of the tongue. On the smooth root of the tongue, three oval vallate papillae are arranged in the form of a triangle, similarly as it is the case in other marsupials. The posterior biggest vallate papilla is oriented perpendicularly to the smaller anterior papillae. The results of the study on the feathertail glider show that the special arrangement of lingual papillae is strongly adapted to feeding behavior of this nectar‐eating and frugivorous animal. Anat Rec, 290:1355–1365, 2007. © 2007 Wiley‐Liss, Inc.     

Comparative morphological study on the lingual papillae and their connective tissue cores in rabbits

The morphological structure of the lingual papillae and their connective tissue cores (CTC) in a rabbit were studied using LM and SEM and were compared to that of other animal species. Externally, the filiform papillae distributed on the anterior surface of the dorsal tongue were short and conical with a round base and had a flat area on their anterior upper half. The CTC of the conical filiform papillae had a roughly triangular plate-like structure with a round top. Several small round protrusions were found on both inclined planes of the triangle. Spearhead-like filiform papillae were distributed on the anterior edge of the lingual prominence and branched filiform papillae were on the posteriorly wide area of the prominence. These papillae on the prominence had a slightly ramified CTC that differed from that of the CTC of the conical filiform papillae distributed on the anterior tongue. Dome-like fungiform papillae were distributed among the conical filiform papillae of the anterior tongue and had a CTC with a roundish structure that was almost but, not quite spherical in appearance with 1 to 10 small round concave indentations for taste buds on their upper surface. The foliate papillae had approximately 15 parallel ridges separated by grooves. These ridges contained a parallel thin plate-like CTC exhibited after removal of the epithelium. The vallate papilla was comprised of a spherical central papilla and had a circular wall with a flower-like CTC almost resembling a carnation. The stereostructure of the rabbit's filiform CTC are comparatively described as being morphologically in between those of rodents and those of the guinea pig and Japanese serow. Such evolution has probably occurred due to the species unique masticatory and gustatory needs and functions.     

Morphology of the dorsal lingual papillae in the newborn panther and Asian black bear

The dorsal lingual surfaces of a newborn panther (Panthera pardus) and two newborn asian black bears (Selenarctos thibetanus) were examined by scanning electron microscopy (SEM). The tongues of the panther and asian black bear were about 40 mm in length and about 20 mm in width. Filiform, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. In the panther, the filiform papillae on margin of the lingual apex were divided into two shapes which were horny or club-shaped papillae. The filiform papillae on the midportion were larger than those on the lateral region in size. The fungiform papillae also were divided into two shapes which were hemispherical or club-shaped papillae. In the asian black bear, the filiform papillae on the margin of the lingual apex were larger than those on margin of the panther tongue. The vallate papillae in the animals of two species were located on both sides of the posterior end of the lingual body. Each papilla was surrounded by a groove and crescent pad.     

Histological pattern of the tongue in the Japanese weasels, Mustela itatsi, with special reference to the morphology and distribution of papillae, taste buds and lingual glands

Light and scanning electron microscopical demonstrations were carried out on the tongues of adult Japanese weasels (Mustela itatsi). Four types of papillae are present on the mucous membrane of the tongue; filiform, fungiform, vallate and foliate papillae. The vallate and foliate papillae are furnished with taste buds. Three types of lingual glands are present in the tongue; mucous (Weber's), serous (Ebner's) and mixed glands. Weber's glands are compound tubular glands which are well developed near the radix. Ebner's glands are compound tubular glands connected with the vallate papillae. Mixed glands are compound tubulo-alveolar glands and present in the lower half of the tongue, near the apex.     

Morphology of the lingual papillae in the Patagonian cavy

We examined the dorsal lingual surfaces of an adult Patagonian cavy (Dolichotis patagonum) by scanning electron microscopy. The tongue of the Patagonian cavy is about 8 cm long and the lingual body had lingual prominence on the posterior third. There were no fungiform papillae in the lingual dorsal surface. The fungiform papillae were observed in both lateral sides of the lingual apex. The filiform papilla of the lingual body consisted of a large conical papilla. The connective tissue core of the filiform papilla showed many slender processes. The fungiform papillae were round in shape. The connective tissue core of the fungiform papilla was flower-bud shaped. Two vallate papillae were located on between lingual body and root, and insert in two grooves. The connective tissue core of the vallate papilla was 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 vertical depressions became apparent. These findings suggest that in the structure of the lingual papillae of the Patagonian cavy there is similar to that of the capybara.     

Morphology of the dorsal lingual papillae in the blackbuck, Antilope cervicapra

The dorsal lingual surface of a blackbuck (Antilope cervicapra) was examined by scanning electron microscopy (SEM). The tongue was about 125 mm in length. There were about 30 vallate papillae on both sides. Filiform, conical, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue, excepted for the lingual torus where conical papillae were present. The fugiform papillae were present rounded bodies, and more densely distributed on the tip and ventral surface of ligual apex. No foliate papillae were seen on the dorsal surface. The vallate papillae were located on both sides of the midline in the caudal part. Each papilla was surrounded by a groove. These findings indicate that the tongue of the blackbuck is similar to that of the formosan and japanese serow.     

The scanning electron microscopic study of lingual papillae in the silver fox (Vulpes vulpes fulva, Desmarest, 1820)

The tongues of adult silver foxes were studied using scanning electron microscopy. Five types of lingual papillae were found on the dorsal surface of the tongue. The most numerous papillae were filiform papillae covering the apex and body of the tongue. The filiform papillae on the anterior part of the tongue are divided into 1 main and 10-12 accessory processes. In the posterior part of the body of the tongue the number of accessory processes is reduced. Fungiform papillae are located between the filiform papillae. A cluster of 12 large fungiform papillae was found on the apex of the tongue. Conical papillae are located in the area of the vallate papillae and cover the posterior part of the root of the tongue. Their size increases towards the pharynx, where they are distributed more sparsely. In the silver foxes there were two pairs of vallate papillae. The wall surrounding each papilla and its gustatory trench forms partly connected 6-8 conical papillae. The foliate papillae on both margins of the tongue body are small and consist of 4-5 laminae. The distribution and type of lingual papillae found in the silver fox are similar to those in the other species belonging to the family Canidae.     

SEM study on the dorsal lingual surface of the large flying fox,Pteropus vampyrus

The dorsal lingual surface of the large flying foxes were examined by scanning electron microscopy. Filiform, fungiform and vallate papillae were observed. The filiform papillae were distributed over the entire dorsal surface of the tongue. The filiform papillae notably differed in morphology by their location on the tongue and could be classified into 6 types: 1) scale-like, 2) giant trifid, 3) small crown-like, 4) large crown-like, 5) long conical and 6) short conical papillae. The fungiform papillae were present rounded bodies on the anterior 2/3 of the tongue. The large flying foxes showed the triangular arrangement of the three vallate papillae, with the apex of the triangle directed posteriorly. These findings indicate that the tongue of the large flying bat is similar to that of the lesser dog-faced fruit bat.