Relação entre a divergência de nicho e as características fenotípicas dos canídeos da América do Sul

Abstract

The ecological opportunities that result from the colonization of new environments can favor the morphological and ecological diversification of species. Canids arrived in South America after the formation of the Panama isthmus and underwent a rapid diversification occupying a great variety of habitats across the continent. We analyzed, in a phylogenetic context, the evolution and divergence of the morphological and ecological characteristics of eight canid species endemic to South America. To this aim, we employed niche modelling and geometric morphometrics. Also, we tested if the morphological characteristics of the species are related to the diversification of the group in different environments across the continent using distance-based phylogenetic regression. We observed that the characteristics of the climatic niche are independent of the time of divergence of the species. We also found that skull shape does not show phylogenetic structuring and is related to climatic gradients and with properties of the trophic niche. Mandibular shape does show phylogenetic signal and is related to gradients in climate and diet. Body size does not display phylogenetic signal and is related to properties of the trophic niche. Our results evidence that the diversification of the South American canids is related to the divergence and occupation of niches across the continent, and that bioclimatic and trophic niche characteristics have influenced phenotypic evolution of the species. This study presents, for the first time, evidences of a possible adaptive radiation of South American canids at a continental scale.