Scanning Electron Microscopic Study on the Tongue and Lingual Papillae of the adult Spotted Seal, Phoca largha

Abstract

Summary: 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 Vshaped 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 of fungiform 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 Japanese badgers, Meles meles anakuma

“…On the other hand, Shimoda et al (1996), described the surface structure of the filiform papillae of the semi-aquatic Mustelid, Sea otter and noted that the surface structure of the filiform papillae of the Sea otter appeared to be conical shaped and lacked accessory protrusions. Smooth or lacking accessory protrusion on the filiform papillae has also been seen in the other aquatic Arctoidea, such as the California sea lion and Spotted seal (Yoshimura et al, 2002(Yoshimura et al, , 2007. These morphological differences may originate from not only their diets but also their living environment, i.e.…”

“…The mixed dietary life is similar to some of other carnivore species such as raccoons and bears and morphological features especially the surface structure of filiform papillae may be representative of their masticatory method. Yoshimura et al (2002Yoshimura et al ( , 2007, observed the filiform CTCs of other aquatic Arctoidea, such as the Pinnipedia; California sea lion and Spotted seal. Filiform CTCs of the California sea lion appeared as thick conical shaped main processes, which were covered with numerous small rod-like secondary processes.…”

Light and Scanning Electron Microscopic Study on the Tongue and Lingual Papillae of the Common raccoon, Procyon lotor

“…CTC of filiform papillae in Pinnipeds seem to be varied compared with those in the terrestrial Arctoid; where CTCs of filiform papillae appear thick conical shaped with numerous small, studded projections but no concavities were found in front of the CTCs [California sea lion; Yoshimura et al, (2002)]. In contrast, filiform CTCs of the Spotted seal exhibit a primary core associated with approximately 5-15 accessory cores (Yoshimura et al, 2007) and are comparatively similar to terrestrial Arctoid species. Filiform CTC of Canidae, sister clade of Arctoidea, morphology also resembles that of the domestic dog with an oval concavity and a main protrusion situated on the posterior end of concavity (Kobayashi et al, 1992).…”

“…Among other Arctoid species, the presence of fungiform CTC vary; fungiform CTCs of the Japanese black bear (Inatomi and Kobayashi, 1999) (Yoshimura et al, 2002) have a bulbous appearance with numerous small rod-like secondary cores being densely distributed on its surface. CTCs of fungiform papillae on the spotted seal's tongue (Yoshimura et al, 2007) appear as a cylindrical primary core with numerous rod-shaped accessory protrusions arranged on the lateral side of the cylindrical cores. Fungiform CTCs of the spotted seal had similarity with those in the Red panda and/or Japanese badger.…”

“…Ferret and Japanese weasels (Emura, 2007) have four and the Siberian weasel has six vallate papillae. Pinnipeds such as the California sea lion have five vallate papillae (Yoshimura et al, 2002) and the Spotted seal has 6-7 vallate papillae (Yoshimura et al, 2007) arranged in a V-shape. Domestic dogs have 4-7 vallate papillae (Sonntag, 1925).…”