Diversification patterns in the North Andean Block: a perspective from biogeographical hypotheses

We used 637 species from six taxonomic classes to identify the pattern(s) of diversification, occurring in the North Andean Block estimating phylogenetic relationships, divergence times, dispersal-vicariance events, and ancestral distributions. We assessed four hypotheses that explain the diversification in the NAB. For each hypothesis, we specified: three sets of unequal rates of dispersal between areas and a temporal stratification, containing four-time intervals for the Miocene. The North Andean taxa showed three ancestral distributions such as the Amazonian region, Central America, and Central Andes where we recovered the major dispersal events. The pattern from North Andean Cordilleras to lowlands fit better the diversification inside the NAB. However, according to the smaller log-likelihood deltas obtained between hypotheses, the taxa followed two patterns, from lowlands to highlands and vice-versa. We found seven out of 15 groups that diversified at the rhythm of the North Andean uplift showing different times to reach each Cordillera. The south-to-north pattern was supported by 80% of the groups. Furthermore, exchanges between South and Central America were identified occurring between 15 to 10 Ma. The two altitudinal patterns from lowlands to North Andean Cordilleras and vice-versa are plausible regardless the ancestral area estimated, and these patterns occurred multiple times in the same temporal frame (Miocene). However, the pattern from North Andean Cordilleras to lowlands fit better which might support a highlands origin inside or outside the NAB. Finally, the North Andean taxa followed the mountain building scenario, where the Central Cordillera raised first, later the Western Cordillera, and last the Eastern Cordillera.