Sexual dimorphism in five species of mountain lizards

Gender differences on thermal biology could relax ecological competition between males and females. Male-biased sexual size dimorphism could relate to different selection pressures in males and females, within increasing fitness conferred on larger males. We studied sexual dimorphism regarding body size, forelimb lenght and head shape of five of the seven species of Iberolacerta lizards of the Iberian Peninsula. In order to stantarize the data among species we compared the log ratios of the sexual size dimorphism (SSD) and the sexual shape dimorphism (SShD). Results revealed that SSD was only significan for two of the five species, while males and females show similar body size for the other three species. However, regarding SShD, males have proportionally longer forelimbs than females in the five species, being this effect bigger in I. cyreni and I. monticola, intermediate I. galani and smaller in I. bonnali and I. aurelioi. The same was observed for the proportional lenght and hight of the head. Nonetheless, males had proportionally wider heads in I. cyreni and I. monticola, intermediate in I. bonnali and smaller in I. galani and I. aurelioi. In summary, I. galani males are proportionally longer regarding females in comparison with the general morphological pattern of the genus and I. bonnali males have proportionally wider heads than females than the general morphological pattern. Territorial competition between males of I. bonnali in an isolated habitat could explain the selection for males with wider heads in I. bonalli, while enhanced fitness of faster males could explain the observed pattern of I. galani. In any case, the patterns of sexual sex dimorphism of Iberolacerta studied in the present research will throw light in the selective patterns driving the evolution of the morphology of lacertid lizards.