title: Structural characterization of the capybara (Hydrochaeris hydrochaeris) tongue by light, scanning, and transmission electron microscopy.
abstract: Capybara is the largest rodent in the world and displays a seasonally dependent herbivore feeding behavior. Here, we present an anatomical contribution for understand this fact, by light, scanning, and transmission electron microscopy methodologies for tongue tissue analysis. The histological preparations revealed filiform, fungiform, vallate, and foliate papillae on the dorsal mucosa of the capybara tongue. The epithelial layer exhibited a lining of keratinized stratified squamous epithelial cells. The lamina propria was characterized by a dense connective tissue composed of the primary and secondary papillar projections. We also revealed the original aspects of the connective papillae. The shapes of the papillae varied by region of the tongue, and filiform, fungiform, vallate, and foliate papillae and subjacent layers of muscular fibers were observed. Pyriform taste buds occupying the epithelial layer of fungiform, vallate and foliate papillae were identified and the intracellular components of the taste buds and the intracorpuscular amyelinated nerve fibers were observed. The taste buds were characterized by the distribution of granular endoplasmic reticulum throughout the perinuclear area, the Golgi apparatus, and mitochondrial assemblies of various distinct diameters. Mitochondrial accumulation was also observed in the collagen bundle-surrounded amyelinated nerve fibers beside the basal cells. Therefore, these peculiar anatomical descriptions may contribute to understanding the adaptation of the feeding behavior of capybaras in a seasonally changing environment.
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Brazil. watanabe@icb.usp.br
authors.forename: Ii-Sei
authors.initials: IS
authors.lastname: Watanabe
authors.forename: Carlos Alexandre
authors.initials: CA
authors.lastname: Dos Santos Haemmerle
authors.forename: Fernando José
authors.initials: FJ
authors.lastname: Dias
authors.forename: Diego Pulzatto
authors.initials: DP
authors.lastname: Cury
authors.forename: Marcelo Cavenaghi Pereira
authors.initials: MC
authors.lastname: Da Silva
authors.forename: Marcia Consentino Kronka
authors.initials: MC
authors.lastname: Sosthines
authors.forename: Tatiana Carlesco
authors.initials: TC
authors.lastname: Dos Santos
authors.forename: Juliana Plácido
authors.initials: JP
authors.lastname: Guimarães
authors.forename: Maria Angélica
authors.initials: MA
authors.lastname: Miglino
mesh_terms: D000818:Animals; D008853:Microscopy; D008854:Microscopy, Electron; D009061:Mouth Mucosa / Q000166:cytology* / Q000648:ultrastructure*; D012377:Rodentia / Q000033:anatomy & histology*; D014059:Tongue / Q000166:cytology* / Q000648:ultrastructure*