Morphological and ecological divergence in South American canids

Aim Closely related species are expected to be similar in their ecological attributes. However, clades colonizing new environments and diversifying due to ecological processes often show morphological and ecological divergence. Canids arrived in South America after the formation of the Isthmus of Panama and diversified to occupy a variety of habitats. We test whether the diversification of this group was followed by divergence in species niches. If ecological processes are associated with species divergences, we expect to see species occupying distinct climatic niches, showing divergent phenotypes, and showing a close association between their phenotypes and ecological attributes. Location South America Methods We use comparative and multivariate climatic niche analysis, geometric morphometric (skull and jaw), and distance-based phylogenetic regressions to test whether the diversification of South American canids was followed by divergence in their climatic niches and phenotypic traits. Results We found a pattern of continental niche occupancy (north to south) along a complex climatic gradient. As species diverged, they evolved distinct climatic tolerances. Climatic niche similarities are not related to species phylogenetic relationships, indicating that closely related species may have distinct climatic tolerances. Our morphological analysis also showed strong phenotypic divergence between species. Our results suggest that these differences were related to climatic and trophic niches. Results show divergent phenotypes in both the skull and jaw, and that there is a close association between phenotype and ecological strategies. Main conclusions Our study integrates phylogenetic history, ecological and morphological data to study the evolution of South American canids. Canid colonization of South America was followed by species ecological divergences. Our results support the hypothesis that ecological processes are the main drivers of diversification of this clade and illustrate a complex biogeographical history of ecological diversification of canids at continental scale.