ORIGINAL ARTICLE Direct long-distance dispersal shapes a New World amphitropical disjunction in the dispersal-limited dung moss Tetraplodon (Bryopsida: Splachnaceae) Lily R. Lewis 1 *, Ricardo Rozzi 2,3 and Bernard Goffinet 1 1 Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA, 2 Omora Ethnobotanical Park, Institute of Ecology and Biodiversity, and Universidad de Magallanes, Puerto Williams, Antarctic Province, Chile, 3 Department of Philosophy, University of North Texas, Denton, TX 76201, USA *Correspondence: Lily R. Lewis, Ecology and Evolutionary Biology, University of Connecticut, 75 N Eagleville Road, U-3043, Storrs, CT 06269, USA. E-mail: Lily.Lewis@uconn.edu ABSTRACT Aim Many intercontinental disjunctions, especially among spore-producing plants, are shaped by long-distance dispersal (LDD) via wind currents. Amphi- tropical disjunctions are most commonly explained through LDD, but other vectors and dispersal scenarios must also be considered. To interpret the New World amphitropical disjunction in the dung-moss genus Tetraplodon, we compared stepwise migration along the Andes, direct LDD and ancient vicariance. Location Global, specifically high-latitude and high-elevation localities, with a focus on the New World. Methods Phylogenetic relationships were inferred from four loci sampled from 124 populations representing the global range of Tetraplodon, and analy- sed using maximum-likelihood and Bayesian optimality criteria, with diver- gence dates estimated in beast. Results The monophyletic T. mnioides complex diversified between the early Miocene and early-to-mid Pliocene into three well-supported clades, each with a unique geographical distribution: Laurasian, primarily high-elevation tropical, and amphitropical. Populations from southernmost South American were reconstructed as a monophyletic lineage that diverged from high-latitude Northern Hemisphere populations around 8.63 Ma [95% highest posterior density (HPD) 3.07–10.11 Ma]. Main conclusions Direct LDD has resulted in the American amphitropical disjunction in Tetraplodon. A lack of modern or historical wind connectivity between polar regions and the poor resistance of Tetraplodon spores to the conditions associated with wind-dispersal suggest that bird-mediated LDD pro- vides the best explanation for the establishment of amphitropicality. Keywords Amphitropical, bipolar, bryophyte, disjunctions, long-distance dispersal, migratory shorebird, New World, Tetraplodon. INTRODUCTION Intercontinental disjunctions are common among land plants and may be shaped by vicariance (Raven & Axelrod, 1974), dispersal (Nathan, 2006) or a combination of both processes (Cook & Crisp, 2005). Molecular tools and dating approaches have provided increasing support for the signifi- cance of dispersal in shaping modern disjunctions (de Que- iroz, 2005; Heinrichs et al., 2009). In both the Northern and Southern Hemispheres, wind serves as an important vector for long-distance dispersal (LDD; Mu~ noz et al., 2004; Wil- kinson et al., 2012). Disjunctions between antipodal high lat- itudes (i.e. amphitropical disjunctions), and in some cases low-latitude, high-elevation localities, have also been largely shaped by LDD, according to inferences based on molecular phylogenetic topologies (see Wen & Ickert-Bond, 2009, for review) and dating (Gussarova et al., 2008; Popp et al., 2011; Fernandez-Mendoza & Printzen, 2013). An absence of wind connectivity across the equator due to the Intertropical Con- vergence Zone (Hyeong et al., 2005) has led to the proposal ª 2014 John Wiley & Sons Ltd http://wileyonlinelibrary.com/journal/jbi 2385 doi:10.1111/jbi.12385 Journal of Biogeography (J. Biogeogr.) (2014) 41, 2385–2395