Morphology and histology of female reproductive tract of the dog-faced water snake cerberus rynchops (Schneider, 1799)

Abstract

© 2020 by Maejo University, San Sai, Chiang Mai, 50290 Thailand. The development of viviparity, live-bearing, is an ill-defined evolutionary event that is considered to have emerged in several lineages of reptiles. Therefore, the knowledge from a wide variety of viviparous species will offer better insight into understanding the reproductive adaptations associated with the development of viviparity. The dog-faced water snake, Cerberus rynchops, belongs to the family Homalopsidae that is considered to be viviparous, but detailed reproductive features are still poorly known for this species. In this study we investigated the female reproductive system of mature C. rynchops using histological techniques. A paired ovary was anchored to the kidney in this species. Eight to nine ovarian follicles were observed and classified as previtellogenic follicles, vitellogenic follicles and atretic follicles. The oviductal structure of C. rynchops was divided into four regions, namely infundibulum, uterine tube, uterus and vagina, and all oviductal regions were covered with ciliated and non-ciliated cuboidal epithelial cells and surrounded by connective tissue of submucosa, a thick layer of the muscularis and serosa. In the uterus we observed the uterine glands, which are commonly present in viviparous snakes.