Sexual size dimorphism in a Tunisian painted frog (Discoglossus pictus auritus) population

Sexual size dimorphism is a hot topic in evolutionary ecology as it is influenced by a plethora of selective pressures. In this study, we investigated this issue in a painted frog Discoglossus pictus auritus population from south Tunisia, while controlling for age effects. Our results showed no significant sexual dimorphism in body size, classifying the painted frog among the few anuran species where the females are not larger than the males. However, foot webbing length showed a significant male-biased dimorphism, a pattern that may reflect selective pressure favoring swimming in males. Enlarged webbings could possibly improve a male’s mating success through greater aptitudes to win competition against rivals for egg fertilization. Therefore, our findings suggest a male-biased dimorphism in a locomotion-related character in an anuran species, a trait possibly under sexual selection.