Data from: At the passing gate: past introgression in the process of species formation between Amazilia violiceps and A. viridifrons hummingbirds along the Mexican Transition Zone
Rodríguez-Gómez, Flor; Ornelas, Juan Francisco (2016), Data from: At the passing gate: past introgression in the process of species formation between Amazilia violiceps and A. viridifrons hummingbirds along the Mexican Transition Zone, Dryad, Dataset, https://doi.org/10.5061/dryad.89kq4
Aim: We tested whether populations of violet-crowned and green-fronted hummingbirds, Amazilia violiceps and Amazilia viridifrons, are genetically and environmentally differentiated, and examined the role of past geological and climatic changes in driving their diversification. Location: Trans-Mexican Volcanic Belt. Methods: Mitochondrial and nuclear DNA of individuals collected throughout the species' ranges were sequenced and then analysed using maximum-likelihood and Bayesian approaches. Species tree analysis, Bayesian species delimitation, divergence time inference, historical demography, palaeodistribution modelling, and niche divergence tests were used to reconstruct the evolutionary history of the Amazilia species, and the isolation-with-migration coalescent model was assessed to determine whether genetic divergence between Amazilia species occurred in the presence of gene flow. Results: Genetic divergence between A. violiceps and A. viridifrons was shallow, with incomplete lineage sorting and introgression. Species delimitation supported three independent lineages: A. violiceps populations located north of the Trans-Mexican Volcanic Belt; a mixture of A. violiceps south of the volcanic belt and A. viridifrons populations; and A. villadai populations east of the Isthmus of Tehuantepec. Gene flow and divergence time estimates, and demographic and palaeodistribution patterns support the model of species diversification by isolation with migration and habitat shifting in response to Pleistocene climatic fluctuations. Main conclusions: The process of speciation in the Amazilia species complex may be explained by the combined effects of isolation resulting from the Trans-Mexican Volcanic Belt and the lowlands at the Isthmus of Tehuantepec and habitat shifting in response to Quaternary climatic changes.