The Male Urogenital System of the Siberian Salamander Salamandrella keyserlingii (Caudata: Hynobiidae) with Special Reference to the Microstructure of the Testes and Sperm Transport Complex

Abstract

The gross anatomy of the urogenital system and histology of the testes and sperm transport system in adult male Salamandrella keyserlingii from southeast of Western Siberia were examined. The general structure of the male urogenital system in S. keyserlingii was similar to that of other hynobiids. Testes were monolobed and bean shaped. No spermatogenic wave through the longitudinal axis of the testes was observed. However, a «lobular wave» with zonal distribution of cysts at different sperm maturation stages was observed along the proximo-distal axis of each seminiferous lobule. From the testes to the cloaca, the sperm transport system included the vasa efferentia, longitudinal collecting ducts of the vasa efferentia, nephrons of the genital kidneys, collecting ducts, and Wolffian ducts.