title: An atypical reproductive cycle in a common viviparous Asia Agamid Phrynocephalus vlangalii.
abstract: Viviparous lizards living in cold climate of high altitude often exhibit atypical reproductive cycles, in which mating and fertilization occur synchronously and annually with parturition occurring at the end of the year. Nevertheless, detailed case studies on atypical reproductive cycles are few. Using anatomical data combined with behavioral observations, we examined the reproductive cycle of a common Asian agamid, Phrynocephalus vlangalii, from a high-elevation area in Sichuan, China. Male spermiation of P. vlangalii occurred in May, and spermatogenesis began in June and reached a maximum in October. For females, ovulation and fertilization occurred in May, and females developed gestation and pregnancy in 3 months from June to August, without vitellogenesis during this period. Females gave birth synchronously in late August, then vitellogenesis began and lasted until May of the next year. All adult males and females were synchronized in the same reproductive condition each month. The synchronous and annual reproductive cycle of P. vlangalii clearly represents an atypical cycle. The male courtship and mating behaviors were concordant with gonadal cycle and mainly happened in May and June. Despite the short growth period for neonates, they had a high over-winter survival rate of 84.4%, suggesting that autumn parturition did not generate high costs to this reproductive cycle. We propose that the high over-winter survival rate of neonates is likely linked with female delayed sexual maturity, female asynchronous vitellogenesis and gestation, large relative clutch mass (RCM), and adult-offspring burrow sharing behavior during hibernation.
authors.affiliation: Herpetological Department Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan 610041 China ; College of Life Science Sichuan University Chengdu 610064 China ; University of Chinese Academy of Sciences Beijing 100049 China.
authors.forename: Yayong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Departments of Integrative Biology University of Guelph Guelph Ontario N1G 2W1 Canada.
authors.forename: Jinzhong
authors.initials: J
authors.lastname: Fu
authors.affiliation: College of Life Science Sichuan University Chengdu 610064 China.
authors.forename: Bisong
authors.initials: B
authors.lastname: Yue
authors.affiliation: Herpetological Department Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan 610041 China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Qi
keywords: Asynchronous vitellogenesis and gestation; Phrynocephalus vlangalii; relative clutch mass; reproductive cycle; sexual maturity