The female reproductive cycle of the lizard, Cordylus polyzonus polyzonus (Sauria: Cordylidae) in the Orange Free State

Abstract

Winter reproductive activity is exhibited by females of the viviparous lizard, Cordylus p.polyzonus. Vitellogenesis commences in May (autumn), continuing throughout the winter months with ovulation in October. Females are pregnant during summer and give birth in late summer (February). Clutch size is positively correlated to female body size. During embryonic development, ovarian follicles remain small and translucent and the corpora lutea progressively decrease in size until parturition occurs. Embryonic growth was characterized by a concomitant decline in embryonic yolk mass. Although considerable variation was observed in the fat body mass, maximal fat body mass peaked in winter (June) and in mid-summer (December). The onset of vitellogenesis corresponded to declining photoperiod and environmental temperatures.