ORIGINAL ARTICLE Multiple speciation across the Andes and throughout Amazonia: the case of the spot-backed antbird species complex (Hylophylax naevius/ Hylophylax naevioides) Alexandre M. Fernandes 1,2 *, Michael Wink 2 , Carla H. Sardelli 1 and Alexandre Aleixo 1 1 Coordenac ß~ ao de Zoologia, Museu Paraense Em  ılio Goeldi, Bel  em, PA, Brazil, 2 Department of Biology, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany *Correspondence: Alexandre M. Fernandes, Colec ß~ ao Ornitol ogica, Museu Paraense Em  ılio Goeldi, CEP 66040-170, Bel  em-PA, Brazil. E-mail: alexandrefernandes@museu-goeldi.br 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. naevi- oides 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 b-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 differ- entiation, 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. Keywords Amazon Basin, Andes uplift, Aves, cryptic speciation, drainage capture, histor- ical biogeography, Neotropics, river barriers, river refuge hypothesis, Thamno- philidae. INTRODUCTION The high number of species complexes in Amazonia is attrib- uted to the existence of large rivers that function as geo- graphical barriers (Haffer, 1974). Closely related taxa of birds, commonly referred to as superspecies (or species com- plexes), exist on opposite sides of the large rivers throughout Amazonia. They are thus likely to be young and monophy- letic (i.e. have a common most recent ancestor) (Haffer, 1969). This pattern of distribution offers a good opportunity to study relationships within the biota and to provide infor- mation critical for understanding the biological diversifica- tion in Amazonia. Wallace (1852) was the first to note that range boundaries of animals in Amazonia seemed to coincide with the rivers, forming so-called ‘areas of endemism’ (Cracraft, 1985). However, more refined data on the geographical distribution and molecular phylogenies of Amazonian birds and primates ª 2014 John Wiley & Sons Ltd http://wileyonlinelibrary.com/journal/jbi 1 doi:10.1111/jbi.12277 Journal of Biogeography (J. Biogeogr.) (2014)