Drivers of Andean diversity: Phylogeographic structure and the evolution of hemipenial and dewlap morphology in a Neotropical lizard (Squamata: Anolidae: Anolis mariarum)

Abstract

Abstract Phenotypic traits and genetic variation are fundamental for understanding biological diversity and evolutionary processes. In natural populations, phenotypic novelties are generally expected to align with genetic differentiation, establishing phenotype–genotype relationships. This pattern is evident in Neotropical lizards of the genus Anolis , where traits such as the dewlap and hemipenes play key roles in species recognition and sexual selection, and are often associated with reproductive isolation, genetic structure, and lineage divergence. However, in Anolis mariarum , an Andean species from northern Colombia, previous limited sampling suggested a mismatch between these traits and the mitochondrial DNA (mtDNA) lineages. Here, we analyzed specimens from 41 localities across the species’ range, examining hemipenial morphology, dewlap coloration, phylogenetic signal, and genetic structure using three mitochondrial markers. We identified seven mitochondrial clades within A. mariarum , with divergence partially shaped by Andean topography and genetic distances comparable to those reported among Anolis species and subspecies. Two hemipenial morphologies (types A and B) and three dewlap colour patterns (orange–yellow, orange–pink, reddish) were detected, reflecting notable intraspecific variation. Although both traits showed strong phylogenetic signal, they exhibited weak spatial and genetic structuring, suggesting an early stage of divergence. Because our inferences are based exclusively on mtDNA, these results should be interpreted cautiously and provide only a preliminary framework for investigating the evolutionary processes underlying phenotypic diversification. These results highlight the evolutionary relevance of dewlap and hemipenial traits and emphasize the need for extensive morphological, geographic, and genetic sampling to accurately assess lineage boundaries and uncover patterns and processes leading to enormous diversity in Neotropical fauna.