Sexual size dimorphism in selected traits of Leptodactylus luctator (Anura: Leptodactylidae)

Abstract

Sexual dimorphism reveals a broad variation in morphological, physiological, and behavioraltraits related to organismal life strategies. Anurans are particularly suitable for studying theorigin, integration, and diversification of sexual dimorphism, owing to the high degree ofvariation observed in size and secondary sexual characteristics, as well as the diversity of lifehistories and their complex biphasic cycle. In this study, a morphometric characterization ofLeptodactylus luctator is conducted to investigate whether sexual dimorphism is present. Atotal of 18 variables were measured in the head, body, and limbs of males and females from apopulation located in wetlands near Ucacha town, Córdoba Province, Argentina. Leptodactylusluctator exhibited more robust limbs in males, but longer fingers in females. Furthermore, females showed a greater axilla-groin length, indicating differences in body shape between sexesin addition to size. Given that larger forelimbs in males have been associated, in the literature,with greater reproductive success, while finger length has been correlated with different levelsof circulating sex hormones, the possible selection pressures related to the observed variationare discussed herein.