Sexual Dimorphism and Reproductive Characteristics of the Cozumel Spiny Lizard, Sceloporus cozumelae (Squamata: Phrynosomatidae) from Mexico

Abstract: We analyzed sexual dimorphism and reproductive characteristics (minimum size at sexual maturity, clutch size, and reproductive period) of females and males of Sceloporus cozumelae, a species endemic to the Yucatan Peninsula, Mexico, and which belongs to the Sceloporus variabilis group. Sexual dimorphism was recorded, with the males being larger in snout–vent length, head length, head width, forearm length, and tibia length. The average clutch size was 3.4. Females containing eggs and vitellogenic follicles were observed at the same time, indicating that the population produces at least two clutches annually. Minimum size at sexual maturity was similar for both sexes (40 mm), and reproduction, determined according to the months in which gonads were obtained, was synchronous between males and females. The species shows high similarity to populations of S. variabilis in sexual dimorphism and reproductive characteristics; however, it has smaller snout–vent length when compared to other populations of S. variabilis in Mexico.