Morfologia da cavidade orofaríngea e glândula de cheiro do muçuã (Kinosternon scorpioides scorpioides Linnaeus, 1766) de vida livre.

Abstract

The muçuã, as the Kinosternon scorpioides scorpioides is known, is the only representativeofthe Kinosternidae family in Brazil. It is a chelonium with a 15 cm long carapace lengthasanadult. Semiaquatic habit, his diet in free life includes a wide variety of food of plant andanimal origin, being considered omnivorous or generalist opportunist. However, towithstandsummer drought, when climatic and food conditions are unfavorable, the muçuã remains buried beneath the soil, in a state of low metabolism and consuming energy reserves, in a mechanism known as “estivação”. Another peculiarity of the muçuã is to secrete a substance that exudes a strong and characteristic odor produced by scent glands, which is intendedtorepel predators, but can also be used as a sexual attraction. In spite of the badsmell thatexudes, the species is appreciated as a delicacy in the cuisine of the northern regionof Brazil,where the disorderly exploitation has caused substantial decline in natural populations. Thepresent study aimed to describe the morphological aspects of the oropharyngeal cavityandthescent gland of muçuã. The animals were collected in naturally occurring areas, intheMarajóMeso-region in the state of Pará/Brazil. Light microscopy revealed that almost all of theliningepithelium of the oropharyngeal cavity is of the nonkeratinized mucosal stratifiedtype,containing many mucosal cells and numerous epithelial mucus glands throughout thetongue,palate and floor of the oral cavity, except for the region next to the ranfoteca, whichisconstituted by stratified keratinized squamous epithelial tissue containing several gustatorybuds. Scanning electron microscopy showed that all the epitheliumof the oropharyngealcavity presented pores, grooves, microvilli and microrigde. In all specimens analyzed,regardless of sex, four scent glands were found, two axillary pairs and two inguinal pairs, structurally similar to each other. Each gland consisted of a single lobe secretoryholocrinesecretion containing cells formed by two types of secretory vacuoles. Type 1 flushedred,were the largest and most frequent, and were positive for Schiff's Periodic Acid(PAS),suggesting to be a glycoprotein complex and type 2, translucent, smaller and smaller numberand negatives for SBP. The secretion produced was carried by a single duct throughabonycanal existing in the bridge that connects the carapace to the plastron and excretedbyanouterpore located in the respective shield that gives name to the gland. Being a semi-aquaticspecies, the presence of taste buds in the region near the ramphoteca and the absenceofsalivary glands corroborate what is known about the feeding behavior for species, whichseizes the food using the jaw, for flavor perception, and the drags into the water to facilitateswallowing. In free-living animals, the absence of water during the dry season makes food ingestion difficult, and this should be one of the reasons, why the species goes through the stowage process, using only its energy reserves. It is emphasized that to facilitatecaptivemanagement, the species must have its food offered in or near the water slide. Theodorsproduced by the smell glands should influence the behavior of males and females inmanyways and deserve attention, especially in captive animals. Density and sex ratioshouldbetaken into account, especially during the reproductive period, so that there are noagonisticinteractions. Although the openness to captive breeding provided by legislation is extremely important, it is necessary to develop research that fills the gaps of knowledge about thespecies and that makes possible its creation for production.