The biogeographic history of Phoenicurus redstarts reveals an allopatric mode of speciation and an out-of-Himalayas colonization pattern GARY VOELKER 1 , GEORGY SEMENOV 2 , IGOR V. FADEEV 3 , ANNA BLICK 1 & SERGEI V. DROVETSKI 4 1 Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA 2 Institute of Systematics and Ecology of Animals of Siberian Branch of Russian Academy of Sciences, Frunze St. 11, 630091 Novosobirsk, Russia 3 State Darwin Museum, Vavilova St. 57, 117292 Moscow, Russia 4 Department of Natural History, Tromsø University Museum, University of Tromsø  The Arctic University of Norway, PO Box 6050 Langnes, NO-9037 Tromsø, Norway (Received 18 August 2014; accepted 7 November 2014) Montane areas host high levels of diversity and endemism, and these features are tied to habitat stratification along an elevational gradient. As such, montane areas are often thought of as model systems in which sympatric speciation can occur. To test this idea, we selected Phoenicurus redstarts, an avian genus with an extensive distribution across Eurasia, as well as Northwest Africa; nine of the 14 species in the genus have distributions which include the Himalayas. We used sequences of the mtDNA ND2 and cytochrome-b genes and intron 9 of the Z chromosome specific ACO1 gene to reconstruct a phylogeny of the genus. The resulting trees were used to reconstruct a biogeographic history of Phoenicurus, and to date diversification events. We also analysed the relationship between node age and sympatry to determine the geographic mode of speciation in the genus. Our data suggest a very late Miocene, Himalayan origin for Phoenicurus. Diversification and colonization of other parts of Eurasia, as well as Northwest Africa, continued through the Pleistocene, with a rapid pulse of speciation in the late Pliocene. Allopatric speciation was the dominant mode of speciation in Phoenicurus, despite extensive distributional overlaps in the Himalayas where ecological conditions are amenable to speciation in sympatry. Our results, along with several other studies, suggest an emerging pattern where the Himalayas served as a source area for montane specialist avian lineages that subsequently colonized other Palaearctic regions. Key words: allopatric speciation, biogeography, Himalayas, Palaearctic, Phoenicurus, phylogeny Introduction Montane regions are often characterized by sharp eleva- tional habitat gradients and as a function of this, many mountain systems are known hotspots of avian diversity and endemism (Myers, Mittermeier, Mittermeier, da Fon- seca, & Kent, 2000; Orme et al., 2005). This link between elevational gradients and high diversity is thought to pro- vide an opportunity for sympatric speciation (speciation across ecotones; Fjeldsa  & Bowie, 2008). However, sys- tematic and biogeographic studies of birds distributed in montane regions of Central and South America as well as Africa, have shown that closely related lineages, to include sister taxa, are not found in adjacent habitats along elevational gradients. Instead, sister taxa are found in generally similar environments on different mountain ranges, or when found in the same mountain range, they tend to be on different mountains (Barrera-Guzm an, Mil a, S anchez-Gonz alez, & Navarro-Sig€ uenza, 2012; Chaves & Smith, 2011; Guti errez-Pinto et al., 2012). Such patterns suggest an allopatric mode of speciation and indeed allo- patric speciation appears to be the dominant mode of spe- ciation in birds (Barraclough & Vogler, 2000; Chesser & Zink, 1994; Coyne & Price, 2000; Drovetski, 2003; Dro- vetski, Rakovi c, Semenov, Fadeev, & Red’kin, 2014; Drovetski et al., 2004a., 2013; Fitzpatrick & Turelli, 2006; Friesen & Anderson, 1997; Mayr, 1942; Phillimore et al., 2008; Price, 2008). Although evidence for sympatric speciation in birds remains elusive (Phillimore et al., 2008), avian lineages with species distributed in different montane habitats may still provide the most realistic opportunity for detecting ecologically driven lineage divergence that would be con- sistent with speciation in sympatry. The (almost entirely) Palaearctic genus Phoenicurus (redstarts) is one such line- age. The 14 species in the genus Phoenicurus, which includes species formerly placed in Rhyacornis and Chai- marrornis (Voelker, 2010), are distributed in the Atlas Mountains in northwest Africa and broadly across the Correspondence to: Gary Voelker. E-mail: gvoelker@tamu.edu ISSN 1477-2000 print / 1478-0933 online Ó The Trustees of the Natural History Museum, London 2015. All Rights Reserved. http://dx.doi.org/10.1080/14772000.2014.992380 Systematics and Biodiversity (2015), 13(3): 296305 Downloaded by [Texas A&M University Libraries] at 06:47 24 March 2015