Sexual dimorphism and female ecomorphology in Anolis (Squamata: Anolidae): knowledge of female morphology increases the understanding of Anolis diversification

Abstract

The study of sexual dimorphism in Anolis lizards brings the opportunity to understand how this phenomena interacts with adaptive radiation to produce broader diversity. We explored this phenomenon in 43 Anolis species from northwestern South America. Morphometric analysis with body size and shape, and lamellae number, were used to estimate the indexes of size dimorphism, and dimorphism in other ecomorphological traits. Almost half of these species exhibit differences between sexes in all traits, and body size relates to size dimorphism but not to shape dimorphism. When female and male data are analyzed separately, we found four and five morphotypes, respectively. Males and females of 10 species exhibit a huge difference in morphology, and the two sexes in these species were assigned to different morphotypes. In addition, SURFACE analyses reveal that the morphology of sexes evolved towards slightly different adaptive regimes, numbers and patterns, suggesting that the lower female morphological diversity highlights the more conservative nature of the female niches. Finally, our study demonstrates the need for ecological information to explain morphological patterns in dimorphic species, and to further understand the mechanisms that drive the evolution of morphological diversity in this genus.