Age structure, growth and longevity in the common toad, Rhinella arenarum, from Argentina

Abstract

Age structure, growth and longevity was determined in the common toad, Rhinella arenarum, from a suburban pond located in the Pampa plains, central Argentina during two breeding seasons, in 2000 and 2008 by using skeletochronology, which relies on the analysis of the annual lines of arrested growth (LAGs) in bones. Both females and males were captured in 2008, while only males were recorded in 2000. Females were significantly larger than males. Mean population age was 2.4 ± 0.9 years in 2000. In 2008, the difference in age was not significant between the sexes (Males: 3.0 ± 0.7, n = 21; Females: 2.6 ± 0.9, n = 12), neither between males in 2000 and 2008. The longevity in males of 2000 was 6 LAGs and exceeded that of males (5 LAGs) and females (4 LAGs) in 2008. Von Bertalanffy curves showed that the growth coefficient in the males of 2000 (K = 2.97 ± 0.47) was almost double that of females (K = 1.21 ± 0.10) and males (K = 1.01 ± 0.14) of 2008. Males and females Rhinella arenarum show different morphological and life history traits and the year of sampling can significantly influence the estimation of the studied parameters such as age at maturity and growth rates.