GROWTH RATES OF PALEOSUCHUS PALPEBROSUS AT THE SOUTHERN LIMIT OF ITS RANGE

摘要

We estimated growth rates of Dwarf Caiman (Paleosuchus palpebrosus) with capture- recapture data from 40 individuals collected over 6 yr in streams surrounding the Brazilian Pantanal, near the southern limit of the species' distribution. Repeated recaptures of eight animals indicate that withinindividual variation is much greater than between-individual variation, possibly reflecting climatic influences. Growth rates of juveniles increased linearly until individuals were about 28 cm snout-vent length (SVL), and then growth rates decreased gradually after attaining that size. The rate of decrease, however, differed between males and females. Data for 30 juveniles with known age were used to validate the growth curve based on the growth rate-on-size analysis. The length of the smallest female recorded nesting (SVL?60 cm) allowed us to estimate the age at first reproduction to be about 8 yr for females. Our data do not support our initial hypothesis that P. palpebrosus would have slow growth rates and relatively old age at first reproduction, as has been suggested for Paleosuchus trigonatus.