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Keywords:

  • Amazon Basin;
  • Andes uplift;
  • Aves;
  • cryptic speciation;
  • drainage capture;
  • historical biogeography;
  • Neotropics;
  • river barriers;
  • river refuge hypothesis;
  • Thamnophilidae

Abstract

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 [1015 bp of cytochrome b (cyt b) and 1023 bp of NADH dehydrogenase subunit 2 (ND2)] and one nuclear marker [539 bp of intron 5 of the β-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.