Reproductive Strategy and Cycle of the Toad-headed Agama Phrynocephalus grumgrzimailoi (Agamidae) in Xinjiang, China

The reproductive strategy and cycle of Phrynocephalus grumgrzimailoi were studied at a locality close to Urumqi City, Xinjiang, China. The hatchlings of P. grumgrzimailoi need at least two years to reach sexual maturity, with the smallest mature male and female measured 48.02 mm and 47.01 mm snout-vent length (SVL), respectively. Adult females produce a single clutch per breeding season, with the clutch size ranging from 1 to 5. The clutch size and mass are significantly correlated with female SVL. There is no correlation of mean egg size with clutch size and relative fecundity in P. grumgrzimailoi, suggesting that the trade-off is absent between mean egg size and number. Females increase reproductive output mainly through increasing egg numbers. The copulation period lasts from April to June. Females begin vitellogenesis in April and lay eggs from May to July. Our results suggest that toad-headed lizards tend to select different reproductive strategies to adapt themselves to their arid or semi-arid habitats.