A likelihood inference of historical biogeography in the world's most diverse terrestrial vertebrate genus: Diversification of direct-developing frogs (Craugastoridae: Pristimantis) across the Neotropics

- Biogeography of Pristimantis was inferred from multigene phylogenetic analysis.
- Northwestern Andes are the most likely origin of Pristimantis.
- Mid-elevation ranges between 1000 and 3000 m were key factors in Pristimantis radiation.
- The uplift between north and central Andes generated a bridge of highland species.

The geology of the northern Andean region has driven the evolutionary history of Neotropical fauna through the creation of barriers and connections that have resulted in speciation and dispersal events, respectively. One of the most conspicuous groups of anuran fauna in the Andes and surrounding areas is the direct-developing species of the genus Pristimantis. We investigated the molecular phylogenetic placement of 12 species from the montane Andes of Colombia in a broader geographical context with a new genus-level phylogeny in order to identify the role of Andean orogeny over the last 40 million years and the effect of elevational differences in diversification of Pristimantis. We examined the biogeographic history of the genus using ancestral range reconstruction by biogeographic regions and elevational ranges. We recognized the middle elevational band (between 1000 and 3000 m) in the Northwestern Andes region of Colombia and Ecuador as a focal point for the origin and radiation of Pristimantis species. Additionally, we found several Andean migrations toward new habitats in Central Andes and Merida Andes for some species groups. We suggest that the paleogeological changes in the Northwestern Andes were the main promoter of speciation in Pristimantis, and may have served as a corridor for the dispersion of lowland species.