Morphological and histological characterization of sexual segment of the kidney in Notomabuya frenata (Cope, 1862) and Aspronema dorsivittatum (Cope, 1862) (Squamata, Mabuyidae)

The male reproductive cycle of the brown basilisk Basiliscus vittatus (Squamata: Corytophanidae) from Tabasco, Southern Mexico

We used histological and morphometric methods to study the testis and associated glands, including the epididymis, ductus deferens, and renal sexual segment (RSS), of specimens of Basiliscus vittatus sampled from Tabasco, Mexico (17.5926° N, 92.5816° W). Samples were collected throughout 1 year, which included the dry (February to May) and rainy (June to January) seasons. Spermatogenesis in B. vittatus is active throughout the year, but a significant increase in the testicular volume, diameters of seminiferous tubules, height of the germinal epithelium, spermiogenesis, and released spermatozoa occur in the dry season. During the rainy season, all aforementioned parameters decreased except the secretory activity of the epididymis and the RSS, which increased concomitant with an increase of the spermatozoa population within the ductus deferens. These data strongly suggest that B. vittatus reproduce year-round, but males exhibit a peak in spermatogenic activity during the dry season and a peak in insemination and/or copulation at the beginning of the rainy season. We highlight the importance of analyzing not only the testis but also accessory ducts and glands when determining the reproductive cycles of reptiles. The reproductive cycle of B. vittatus is discussed in relation to the environmental conditions of Southern Mexico and is compared to that of other squamates.

Cycle of the sexual segment of the kidney: histological insights into the role of the urinary tract in the reproduction of male Notomabuya frenata (Squamata: Scincidae)

The kidneys of male Squamata have an important reproductive function as some portions of the nephron may undergo hypertrophy, characterizing the sexual segment of the kidney (SSK). Although its function is still not completely understood, it is believed that the secretions produced by the SSK may act in the maintenance of spermatozoa. In this study, we investigated the reproductive biology of males of Notomabuya frenata based on the seasonal variation of the SSK. We performed macroscopic and microscopic evaluations of the male reproductive tract of museum specimens to characterize the SSK cycle. The nephron portion in which hypertrophy was observed was the collecting duct with secretory granules accumulation in the apical portion. SSK hypertrophy was observed in all seasons, with the tubule diameter in autumn differing from spring and the epithelium height showing no variation. Alcian Blue reacted positively to acid mucopolysaccharides in all seasons. Periodic acid-Schiff's reacted positively to neutral mucopolysaccharides in all seasons, except autumn. Both stains reacted only in the collecting duct. In addition, spermatozoa were found in the lumen of the SSK of one specimen examined. Cycle of the SSK varied seasonally as does the chemical composition of the secretions produced by the collecting duct. The reflux of spermatozoa into SSK may indicate that (1) these secretions act in sperm maintenance, and (2) possibly there is communication between the seminal and urinary ducts.

Nomenclature of supra-generic units within the Family Scincidae (Squamata)

The modern classification of skinks is based on a nomenclature that dates to the 1970s. However, there are a number of earlier names in the family group that have been overlooked by recent workers. These names are identified and their validity with respect to the International Code of Zoological Nomenclature investigated, along with their type genera. In most cases, use of these names to supplant junior synonyms in modern day use is avoidable by use of the Reversal of Precedence articles of the Code, but the names remain available in case of future divisions at the tribe and subtribe level. Other names are unavailable due to homonymy, either of their type genera or the stems from similar but non-homonymous type genera. However, the name Egerniini is replaced by Tiliquini, due to a limited timespan of use of Egerniini. A new classification of the Family Scincidae is proposed, providing a more extensive use of Code-regulated levels of classification, including tribes and subtribes, and a detailed synonymy provided for each taxonomic unit.

Sexual segment of the kidney of the lizard, Eutropis carinata: A light microscopic and ultrastructural seasonal study

We studied seasonal variation of the secretory granules in the epithelial cells of the sexual segment of the kidney (SSK) during the annual sexual cycle in the lizard, Eutropis carinata using light and electron microscopy in correlation with measurements of androgen levels. During the breeding phase, the epithelium of the SSK consists of simple columnar cells with basal nuclei. The cytoplasm contains numerous eosinophilic secretory protein and carbohydrate granules, but lacks glycosaminoglycans. These secretory granules develop during the regenerative phase when the circulating testosterone level increase. During the breeding phase, when the circulating testosterone levels are high, three types of secretory granules can be differentiated in the cytoplasm based on size and opacity; electron translucent type I, electron dense type II, and biphasic type III granules. Type II granules are found at various stages of maturity and degeneration/utilization. All types of secretory granules are released through an apocrine process. Microvilli and tight junctions are prominent at the apical portion of the cell. The cytoplasm contains, Golgi complexes, an abundant network of rough endoplasmic reticulum, numerous tubular mitochondria, condensing, mucus filled and empty vacuoles. Intercellular canaliculi are narrow and indistinct during the regenerative and breeding phases, respectively. During the regressed phase, when the circulating testosterone levels are lowest, the cells are found regressed with wide intercellular canaliculi and devoid of secretory granules. Then the cytoplasm contains a few round mitochondria, Golgi and scanty endoplasmic reticulum.