JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Society for the Study of Amphibians and Reptiles is collaborating with JSTOR to digitize, preserve and extend access to Journal of Herpetology. ABSTRACT.-We studied the reproductive cycle of Tropidurus torquatus in the Cerrado biome of central Brazil from October 1997 to September 1998. Females reached sexual maturity at about 65 mm snout-vent length (SVL), whereas males became sexually mature at 70 mm SVL. Females were reproductively active between August and February, although males contained spermatozoa in the epididymides year-round. Frequency of reproductive females was inversely correlated with precipitation and air humidity and positively correlated with day length. Reproductive activity of males was inversely correlated with air humidity and positively correlated with day length. Females laid six eggs on average and may have produced up to three clutches per reproductive season. With the advancement of the reproductive season, clutches tended to be smaller, whereas egg size remained constant Fat body mass varied inversely with reproductive activity in both sexes, but females had significantly larger values than males. After an incubation period of approximately 5 months, young emerged at a SVL around 31 mm. Juveniles began to accumulate energy in fat bodies after reaching 47 mm SVL. The fat body cycle and the recruitment pattern of T. torquatus suggest that food resources are not limiting and that the length of the reproductive season is most likely constrained by the availability of microhabitats suitable for egg development.

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We describe the sexual dimorphism in coloration, body shape, and body size in Tropidurus torquatus, a widely distributed lizard species in central Brazil. Adult males have colored patches varying from yellow to yellow-and-black, and black on the abdomen, ventral aspect of the thighs, and pre-cloacal flap. Adult females lack ventral colored patches. During ontogeny, there is a gradual darkening of the patches, but no modification either in patch size or color is associated with the reproductive cycle. Adult males have wider heads and thinner bodies than females of the same body size. Males and females grow at the same rate prior to sexual maturity, but males take longer to reach sexual maturity, maturing at a larger body size than females.

The demography of the lizard Tropidurus torquatus (Squamata, Tropiduridae) in a highly seasonal Neotropical savanna. The demography of a population of Tropidurus torquatus was studied from March 1996 until December 1998, in the Cerrado biome of central Brazil, using the method of capture and recapture. Population size, number of incoming individuals in the population, and age structure varied seasonally, reflecting the reproductive cycle of the species. The instantaneous rate of population increase did not differ from zero throughout the study. In general, the permanence rates of juveniles and adults were low, indicating a large turnover of individuals in the population, with a maximum life expectancy of three years. The sex-ratio among adults was biased toward females. Since no bias was observed among juveniles and there was no difference in adult permanence between sexes, we suggest that the biased adult sex-ratio resulted from a lower permanence of males during a short ontogenetic period, when secondary sexual characteristics develop. When compared to T. itambere, the studied population of T. torquatus attained a higher density and a greater female bias in the sex-ratio. In general, the studied population presented characteristics that, according to life history theory, should be associated with early age at maturity and polygyny: short life expectancy, high population turn over, and female biased sex-ratios.