Gross and Microscopic Observations on the Lingual Structure of the Florida Manatee Trichechus manatus latirostris

Abstract

The tongue of the Florida manatee (Trichechus manatus latirostris) was studied macroscopically, light and electron microscopically. The tongue was slender, muscular and firmly fixed in the oral cavity; only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral tongue. Multiple raised, round fungiform-like papillae were distributed over most of the dorsum. Typical fungiform papillae were restricted to the lateral margins of the tongue. Foliate papillae, presenting as multi-fossulate openings, were noted on the caudolateral margins. Open pits were located on the dorsocaudal surface and lateral walls. Microscopic examination showed that most of the lingual dorsum was covered with a thick stratified squamous epithelium. Open pits led to well-developed mucous salivary glands. Glands within the foliate papillae were mostly mucous, although some seromucous glands were present. Taste buds were restricted to the epithelium of the foliate papillae. Throughout the tongue, striated muscle was abundant below the epithelium. Blood vessels, lymph channels and nerve fibres were freely distributed throughout the intermuscular stroma. Nerve fibres reacted positively with neurone specific enolase (NSE) antibody throughout the tongue, including nerve bundles, glands and taste buds. Clear to translucent vacuoles were found juxtaposed to nuclei in the stratum spinosum in the foliate papillae epithelium.

Gross and microscopic observations on the lingual structure of the franciscana (Pontoporia blainvillei — gervais and d'orbigny, 1844)

“…Samples from the middle and caudal third were examined histologically and salivary glands beneath the connective tissue layer were observed. This finding was also reported by Levin and Pfeiffer (2002) for the Amazonian manatee (Trichechus inunguis).…”

“…It was covered by a keratinized stratified epithelium. Despite the tongue morphology of mammals being related to their life style, stratification and keratinization are basic and common characteristics of the tongue epithelium in most species of terrestrial (Benetti et al, 2009;Erdunchaolu et al, 2001;Silva, 1999;Watanabe et al, 1992) and aquatic mammals (Guimarães et al 2011;Levin and Pfeiffer, 2002;Yoshimura et al, 2002). Shimoda et al (1996) reported a nonkeratinized stratified epithelium in the tongue of Sea Otter (Enhydra lutris).…”

Tongue papillae morphology of brown-throated sloth Bradypus variegatus (SCHINZ, 1825)

“…Similar structures were described in saru monkeys (Watanabe et al, 1992), camel (Erdunchaolu et al, 2001), Florida manatee (Levin and Pfeiffer, 2002), California sea lion (Yoshimura, 2002), three-toe sloth (Benetti et al, 2009) and squirrel monkey (Branco et al, 2011). Some animals reported by Guimarães (2006) presented non-keratinized stratified pavement epithelium different from the one found in this study.…”

Ultrastructural aspects of Callithrix penicillata lingual papillae

“…In general, the literature reports that in the most primate species, the tongue is composed of three or four types of papillae: filiform, fungiform, vallate, and foliate (not always present in some species). Filiform papilla is the most common (Chamorro et al,1986; Chibugo,1993; Dyce et al,2010; Pfeifer et al,2000; Schwarze and Schröder,1970; Sisson and Grossman,1959), except for the manatee, which has only a small taste of these clusters at the apex of the tongue (Levin,1999).…”