Silva, WF; Lima, RL; Pinheiro, JN; Brito, ES; Ferraz, RHS
Mesoclemmys vanderhaegei (Testudines: Chelidae) is a freshwater turtle with occurrence in Amazon, Tocantins, Paraguai, Parana and Uruguai rivers basins. Although according to International Union for Conservation of Nature, it has low risk of extinction, there is an uptade necessity of ecological and biological data. Considering that the management and conservation plans are related to a wide knowledge of reproductive biology, a first macroscopic description about the young and adults females of M. vanderhaegei is important. These points were correlated to the specimens size and period of the year. The samples of M. vanderhaegei were collected in Chapada dos Guimaraes county, Mato Grosso, Brazil, an area of large natural occurrence of the specimens. Genital organs of seventeen females were fixed in 10% formalin and then dissected to demonstrate the particularities related to external and internal anatomy. The young and adult M. vanderhaegei genitals organs are composed of ovaries and oviducts pairs that dorsolaterally discharge into the cloaca, forming with the ureter, the urogenital papilla. The ovaries are elongated organs with larger cranial and elongated caudal portions. The oviducts, which are in adults very differentiated in its shape and size compared to the young, are long and located laterally to the ovaries. In both age groups, the genital organs are supported by celomatic membrane folds that emerge from the ceiling of the cavity, constituting the mesovary and mesoviduct. In adult females, according to the shape and pattern of the oviduct mucosa, the cranial segment corresponds to the regions of the infundibulum and magnum; the middle segment, the isthmus and the caudal segment identify the uterus and vagina regions. The clitoris is sited on the floor of the urodeum. The carapace linear length and body mass between immature and adult females vary to 134-155.6mm e 134.43-365g respectively. The main part of young females was captured in rainy period and the adults, with and without eggs, at dry period. The macroscopic characteristics of the M. vanderhaegei genital organs are also observed in others Testudines, with the exception of urogenital papilla and by the clitoris presence.