THE OOGENIC CYCLE OF THE DICE SNAKE, NATRIX TESSELLATA TESSELLATA (SERPENTES: COLUBRIDAE) IN NORTHERN IRAN

The dice snake, Natrix tessellata tessellata belongs to the family Colubridae, is an oviparous snake lives mainly in most zones of Iran except eastern south. In this research, the oogenic cycle of Natrix tessellata, was studied in rice lands and rivers of Sari County in Mazandaran Province, northern Iran. Sampling took place periodically every 15 days during the activity period of this species, from 5 April to 5 November 2012. In total, 63 adult females were captured by hand and net. Ovaries and oviducts were removed and processed for histological and morphometrical studies. Oogenesis start at early April, reaching its peak in early and mid June, and ends between early to late July. Oviposition occurred from late June to early August. Folicle number varies between 3-39 in each ovary. The follicle diameter varies between 1.1843.35 mm. The mean diameter of follicular layer and tunica albuginea varies between 40-141 and 13-31.5 micron, respectively. The numbers of oviductal eggs are 1-12 in each oviduct. In Iran, the oogenic cycle of N. tessellata is seasonal and alternate from April to July.