OOMMEN, OOMMEN; MATHEW, SMITA; GEORGE, JANCY; AKBARSHA, M.A; Univ. of Kerala, Kariavattom; Univ. of Kerala, Kariavattom; Bharathidasan Univ. Tiruchirappalli; Bharathidasan Univ. Tiruchirappalli: Ultrastructural studies on Spermatogenesis in Caecilians

The pioneering work on male reproductive biology are those of Seshachar and of late by Wake. The caecilians have evolved a unique pattern of cystic spermatogenesis in which cysts representing different stages in spermatogenesis coexist in a testis lobule. We subjected the testis of ““Ichthyophis tricolor”” and ““Uraeotyphlus cf. narayani”“from Western Ghats of Kerala, India to light and transmission electron microscopic studies. The sequential changes during spermatogenesis in two species were traced for the first time in Gymnophiona. The cell nests were assigned stages in spermatogenesis based on the classification of van Oordt (1956). To the best of our knowledge, this is the first ever identification and /ultrastructural description of stages in spermatogenesis in caecilians and it seems that they appear to have conserved the typical amphibian pattern for the events towards the birth of spermatids. We described spermateleosis in three phases, early, mid and late with the description of the organization of the cells comprehensively, concurrently and chronologically rather than changes leading to the development of acrosome, flagellum nucleus etc. We examined unsettled issues relating to the organization of caecilian testis lobules, including the occurrence of fatty matrix, the possibility of both peripheral and central Sertoli cells; origin of Sertoli cells from follicular cells and the disengagement of older Sertoli cells to become loose central cells. Irespective of the functional status of the testis whether active or regressed, Sertoli cells constitute a permanent feature of the lobule.