Linking genetic, morphological, and ecological divergence in the lizard Liolaemus fuscus : From the Atacama Desert to the Mediterranean ecosystem

Abstract In adaptively radiated groups of organisms, the phenotype is expected to evolve in response to environmental variation in a coordinated way with genetic variation. Some components of the phenotype, such as morphology and habitat use patterns, reflect how organisms interact with their environments and provide insight into their potential adaptations. In this study, we explored the patterns of genetic, morphological, and microhabitat use variation in the lizard Liolaemus fuscus across a ~600 km latitudinal gradient in central Chile. We identified two highly differentiated latitudinally distributed cytb mitochondrial genetic groups, corresponding to the Atacama Desert (Northern clade) and the Mediterranean forests of central Chile (Southern clade). Morphology and habitat use patterns consistently covaried with genetic differentiation. We detected different allometry between clades, as lizards from the Northern clade were significantly shorter and had shorter limbs, heads, and tails at smaller body sizes than lizards from the Southern clade. The lizards from the Northern clade perched more on vegetation, whereas the ones from the Southern clade were more saxicolous and terricolous. Such phenotypic differences could be adaptations to the different environmental conditions, which potentially influenced the differentiation within L. fuscus . The ability of Liolaemus species to respond to environmental variation through coupled genetic and phenotypic differentiation may contribute to their diversification, as expected for adaptive radiations.