Descrição anatomorradiográfica dos dentes da capivara (Hydrochoerus hydrochaeris) / Anatomorradiographic description of the capybara´s teeth (Hydrochoerus hydrochaeris)

ABSTRACT

Background: The capybara (Hydrochoerus hydrochaeris) is the largest South American rodent species alive, and it preferentially inhabits floodable environments. Currently, capybara populations have been increasing owing to lack of predators and increased availability of food. This favors reemergence of Rocky Mountain spotted fever in the state of São Paulo, as these animals can play host to the Cayenne tick (Amblyomma cajennense), a vector of the bacteria that transmit this disease. The objective of this work was to perform anatomical and radiographic analyses on the teeth of capybaras to broaden knowledge on the morphology of this species, as scientific interest on capybaras has been growing owing to reemergence of Rocky Mountain spotted fever.Materials, Methods & Results: Six capybara carcasses from the state of São Paulo, Brazil, were taken to the Laboratory for Animal Anatomy of the School of Agricultural Sciences and Veterinary Medicine of UNESP - Jaboticabal for obtainment of heads by disarticulation of the cervical region. The heads were frozen at -18°C, and then sectioned medially with a band saw to avoid tissue overlap in radiographs. The head halves were radiographed in the Diagnostic Imaging Section at the Veterinary Hospital of UNESP-Jaboticabal in laterolateral projection. After taking the radiographs, the teeth were extracted from the dental arches using anatomical forceps and pliers, placed in 0.1% thymol, and kept at 4°C for up to 30 days. The teeth were dried using an air jet produced by a compressor, and placed in molds made of aluminum foil. The specimens were embedded in alternating layers of clear polymethylmethacrylate and liquid polymerization catalyst until each tooth was completely covered. After 24 h, the molds were removed, and the blocks were sectioned using a band saw. Transversal and longitudinal calcified tooth sections with a thickness of 1.5 mm were prepared.[...]