Anatomy of the female reproductive system and sperm storage of the viviparous caecilian Typhlonectes natans (Gymnophiona: Typhlonectidae)

Abstract

Here, we describe the anatomy of the female reproductive system of the aquatic, viviparous caecilian Typhlonectes natans. We conducted our research on two adult females using light microscopy and reflected our results with the available literature data on the anatomy of the reproductive systems of caecilian amphibians. The female reproductive system of T. natans consisted of longitudinal, paired ovaries incorporated with fat bodies, paired oviducts and the cloaca. The ovaries were arranged in segmental mannered germinal nests and the oocytes were in various stages of development. Ovulated, postvitellogenic oocytes were present in the oviducts of both females. The wall of the oviduct consisted of three layers: the mucous membrane, layers of muscles and serous membrane. The presence of wedge-like cells, not previously reported in the mucous membrane of the caecilian oviduct is postulated. Although the females possessed ovulated eggs, no sperm were detected in any part of the oviducts leaving the question of eventual female sperm storage in Typhlonectes natans open.