Histological changes in the ovary during the annual breeding cycle in Agama impalearis Boettger, 1874 (Reptilia : Agamidae)

The aim of the present work is to investigate the female reproductive cycle of the North African agamid, Agama impalcaris. Histological changes of the whole ovarian cycle were described. Folliculogenesis and oocyte growth were comparable to the general lizard pattern. A single germinal bed per ovary was found. Only previtellogenic follicles were present during the non reproductive period and the onset of vitellogenesis was observed just after emergence from winter dormancy. Two vitellogenic cycles which probably produce two successive clutches per breeding season were observed. The number of vitellogenic follicles can reach 12 per ovarian vitellogenic cycle. The oocyte growth was accompagnied by changes in the theca, granulosa, zona pellucida and zona radiata layers. The postovulatory follicles (corpora lutea) were observed until the onset of the second vitellogenic cycle and disappeared rapidly after them. Two kinds of atretic follicles, hydratation stage and vitellogenic stage atretic follicles, were described. Atresia was less frequent in Agama impalearis and particularly concerned with larger vitellogenic follicles.