The roles of niche divergence, dispersal, and geology on the diversification of Neotropical true frogs from the Rana palmipes species group (Amphibia, Anura, Ranidae) during the Great American Biotic Interchange

Geomorphological changes have played a central role in species diversification by promoting vicariance through barriers that reduce gene flow. However, niche evolution leading to local adaptations to new environments may also drive speciation, regardless of the presence of geographical barriers. Here, we assessed the role of geological changes and climatic niche evolution in the diversification of true frogs of the Rana palmipes species group (Ranidae) in Central and South America. We investigated if the evolutionary history of species was shaped by vicariance and ecological niche conservatism, founder events followed by niche divergence or both by estimating ancestral areas. Then, we used a phyloclimatic analysis to quantify niche overlap and tested for niche conservatism between species. We found a pattern of both vicariance and successive founder events from north to south, with lineages reaching newly formed areas during the formation of Central America throughout the Miocene and Pliocene, and at least two dispersal events into South America. Species presented low overlaps in climatic niche and phyloclimatic analysis did not recover a phylogenetic signal. Profiles of niche occupancy diverging over time and high values of disparity between clades indicate niche divergence during the evolutionary history of species. Our results indicate an interplay between niche evolution and geological changes acting on Rana palmipes species group diversification. Speciation events were probably driven by vicariance and ecological speciation after successive dispersal events, while species occupied new areas available during the uplift of Talamanca and Andes Mountain ranges.

Automated summary

Geomorphological changes and climatic niche evolution have played a significant role in the diversification of true frogs in Central and South America. The evolutionary history of species has been influenced by both vicariance and ecological niche conservatism. Speciation events were likely driven by successive dispersal events and the availability of new areas during geological changes.