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

Abstract

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 toenvironmental changes. The anatomical and histological descriptions ofthe reproductive tract of reptiles are scarce, so it is important to study themorphology of the genital tract of caimans for a better understanding of thereproduction of these species. We performed the histological analysis of thetestis, 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 preparedaccording 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 loosechromatin, and primary spermatocytes show dark cytoplasm, round nuclei,and pale chromatin. Spermatids are seen as cylindrical or filamentous cellswith nuclei that may be highly condensed, ranging from round to oval. Theepididymis is observed as a coiled duct lined by a tall cuboidal epitheliumwith stereocilia; the deferent duct shows ciliated pseudostratified cylindrical epithelium. The adrenal gland is found in the dorsomedial portion of thetestis. The histological structure of the reproductive tract of Paleosuchuspalpebrosus is similar to that of other reptiles’species.