Histological Study of the Male Internal Genital Tract of Dwarf Caiman (Paleosuchus palpebrosus Cuvier, 1807)

摘要

Brazil has six species of crocodiles belonging to the subfamily Caimaninae,one of them being Paleosuchus palpebrosus(Cuvier,1807)(dwarf caiman).It is considered one of the smallest crocodilian species,and is sensitive to environmental changes.The anatomical and histological descriptions of the reproductive tract of reptiles are scarce,so it is important to study the morphology of the genital tract of caimans for a better understanding of the reproduction of these species.We performed the histological analysis of the testis,epididymis,and deferent duct of the dwarf caiman Paleosuchus pal­pebrosus.Structures of the genital tract were collected from euthanized an­imals.Testes,epididymis,and deferent ducts were separated and prepared according to routine histological techniques for morphological characteriza­tion.The testis is covered by a capsule of fibromuscular connective tissue.Spermatogonia are observed as spherical cells with round nuclei and loose chromatin,and primary spermatocytes show dark cytoplasm,round nuclei,and pale chromatin.Spermatids are seen as cylindrical or filamentous cells with nuclei that may be highly condensed,ranging from round to oval.The epididymis is observed as a coiled duct lined by a tall cuboidal epithelium with stereocilia;the deferent duct shows ciliated pseudostratified cylindri­cal epithelium.The adrenal gland is found in the dorsomedial portion of the testis.The histological structure of the reproductive tract of Paleosuchus palpebrosus is similar to that of other reptiles’species.