Age structure of a population of Discoglossus scovazzi Camerano, 1878 (Anura - Discoglossidae) in extreme environmental conditions (High Atlas, Morocco)

Abstract

The age structure and growth of the Moroccan Painted Frog (Discoglossus scovazzi Camerano, 1878) in a population living in the High Atlas at the upper altitudinal limit of the species’ range was estimated for the first time by skeletochronology. Individual age was determined by counting the lines of arrested growth (LAGs) from cross-sections of the phalanges. Both males and females reached sexual maturity at 3-4 years of age at which point the speed of osteogenesis and body growth slow down. Males and females have maximum lifespans of six and five years, and average sizes of 47. 50 mm (n = 21, SD = 1.40) and 39.70 mm (n = 53, SD = 0.90) respectively. We detected a positive relationship between age and size, suggesting that the oldest individuals are always bigger and heavier. Sizes corresponding to the same age class are very heterogeneous reflecting divergent conditions and growth strategies.