The Herpetological Journal

pp.19-26

Authors: Marisa Esteban And Borja Sanchiz

Abstract: Age, body size and histological bone growth were analysed in two populations of Rana iberica that were genetically similar and which represented the attitudinal extremes of the species range. In spite of having a much longer hibernation, mountain frogs were significantly bigger (snout-vent lengths) for all ages, with the exception of the pre-maturity period. Mountain frogs were longer-lived (oldest females 6 years, males 5 years, one male outlier 9 years) than lowland frogs, where at most only one individual of each sex attained the age of 4 years. The minimum age at sexual maturity was 2 years for both sexes and populations. For both sexes, and using different assumptions about the duration of the period of seasonal activity, the relative contribution of the growth rate component seems slightly higher ( 46-75 % for females, 60-82 % for males) than differences in I ife span (i.e. total days of activity: 25-54 % for females, 1 8- 40 % ) in accounting for the overall size differences found between populations.

Keywords: age, altitude, Anura, growth, skeletochronology