REPRODUCTIVE-CYCLES OF PHRYNOCEPHALUS-RET ICULATUS AND PHRYNOCEPHALUS-HELIOSCOPUS (SAURIA, AGAMIDAE)

Reproductive cycles of two sympatric lizards Phrynocephalus reticulatu s and Ph. helioscopus were studied near Bukhara, Southern Uzbekistan, during the period 1989 - 1991. Genital tracts were analyzed in 39 male s and 61 females of Ph. helioscopus. Reproductive cycles of both speci es consist of spring active period, when mating, ovulation, and egg de position take place, summer regressive phase or summer hibernation, au tumn period of recrudescence of gonadal activity, and winter hibernati on. During the period of autumn recrudescence, spermatogenesis is obse rved in both species. This process is accompanied by release of the sp ermatozoa into tubules of the deferent ducts and adequate development of epididymes and by activation of sexual segment in males of Ph. heli oscopus, but not in males of Ph. reticulatus. Females of Ph. helioscop us have a vitellogenic ovarian follicules (d = 3 mm) in November. Sign ificance of such autumn recrudescence of gonadal activity is unclear b ecause nothing is known about winter gonadal condition.