Multiple speciation across the Andes and throughout Amazonia: the case of the spot-backed antbird species complex (Hylophylax naevius/Hylophylaxnaevioides)

Aim To investigate the role of historical processes in the evolution of the spot-backed antbird species complex Hylophylax naevius/Hylophylax naevioides (Aves, Thamnophilidae). Location Throughout the Amazon Basin and across the Andes in Central and northern South America. Methods We investigated the evolutionary history of the H. naevius/H. naevioides complex based on a total of 100 individuals from opposite banks of the major Amazonian rivers and both sides of the Andes. Nucleotide sequences from two mitochondrial DNA genes [1015bp of cytochrome b (cyt b) and 1023bp of NADH dehydrogenase subunit 2 (ND2)] and one nuclear marker [539bp of intron 5 of the beta-fibrinogen (BF5)] were obtained. Phylogenetic relationships were inferred using Bayesian and maximum likelihood methods. We used Bayesian coalescent-based approaches to evaluate demographic changes through time, and to estimate the timing of the diversification events. Results Well-supported allopatric and parapatric lineages were recovered within the H. naevius/H. naevioides complex, with high levels of genetic differentiation, both on opposite sides of rivers (0.6-7.1%) and across the Andes (6.9%). Molecular dating and population demography suggest cladogenesis in various periods, associated with distinct vicariance and dispersal events. Main conclusions Our data support the hypothesis that the uplift of the northern Andes and the consolidation of the modern Amazon drainage system were key to promoting the diversification of forest-dwelling bird lineages in the northern Neotropics.