Annual oviduct cycle in the Indian skipper frog, Rana cyanophlyctis (Schneider 1799): A morphological study

Abstract

Seasonal changes in the weight, diameter, length and histological details of the oviduct were studied in adult Rana cyanophlyctis during the annual reproductive cycle. There are a pair of oviducts in this frog and each one was externally divisible into three segments, i.e., pars recta, pars convoluta and pars uterus. Histologically, the oviduct was composed of outer serosa/peritonial epithelium, middle connective tissue layer (which was very much reduced in thickness) and inner luminal epithelial lining. In the pars recta region, the inner epithelial cells formed longitudinal folds while, in the pars convoluta and pars uterus segments, the epithelial cells differentiated into gland cells and ciliated cells. There was a seasonal variation in the weight, length, diameter of different segments of the oviduct and in the height of the inner epithelial cell lining during the annual cycle. All these parameters were minimum in January (late post-breeding regression phase of reproductive cycle), increased up to September (breeding phase) and then declined following spawning activity. The results suggest that in R. cyanophlyctis, the oviduct undergoes annual variation both in morphology and histological details that depict the functional status of the organ. © 1999 Taylor & Francis Group, LLC.