Caracterização morfo-histológica do segmento sexual renal e espermatogênese de Notomabuya frenata (Cope, 1862) e Aspronema dorsivittatum (Cope, 1862) (Squamata, Mabuyidae)

Abstract

Among the studies on the reproductive characteristics of lizards, many are carried out with species of temperate regions. Different factors may influence the reproductive cycle of neotropical lizard species such as humidity, temperature and rainfall, being the latter determinant in tropical regions. Studies on the reproductive biology of lizards of the genus Mabuya revealed peculiar characteristics of the reproduction and the history of life; with this it can be considered a model taxon for studies on the evolution of the reproductive patterns in vertebrates. The species Notomabuya frenata and Aspronema dorsivittatum, although presenting some known reproductive aspects, many of its characteristics are still unknown. In this context, the objective of the present study was to characterize the morphologically the sexual segment of the kidney (SSK) and the spermatogenesis of N. frenata and A. dorsivittatum. The specimens used in this study were collected in an area of the Cerrado biome in the state of Minas Gerais, Brazil. The kidneys were analyzed by light microscopy and scanning electron microscopy; and the testis only with light microscopy. When analyzing the kidneys, the presence of SSK was only found in sexually mature males. The SSK was coated by high columnar cells with basal nucleus and the apical portion filled with secretory granules; Such morpho-histological characteristics observed in both species are similar to those observed in other studies with different Squamata species. The testes were processed according to standard histology techniques and analyzed by light microscopy. All the adult male specimens analyzed were in the reproductive period, as they had spermatozoa in the testis and / or epididymis. The germinal epithelium of both species was composed of germ cells and Sertoli cells, presenting a continuous reproductive cycle. The epididymis of the species studied was coated by simple xii columnar epithelium, with high cells, basal nucleus and the lumen completely filled by spermatozoa. The specimens of N. frenata and A. dorsivittatum analyzed presented the germinative epithelium organized in a similar way to other Squamata previously studied. There are few studies that address the morpho-histological description of the renal sexual segment, germ cells and spermatogenesis of Brazilian lizards. Thus, the present study not only adds knowledge about reproductive biology in these species, but also aids in a better understanding of reproductive strategy and biology in viviparous and neotropical species.