A dated phylogeny of the palm tribe Chamaedoreeae supports Eocene dispersal between Africa, North and South America Argelia Cuenca a, * , Conny B. Asmussen-Lange a , Finn Borchsenius b a Department of Ecology, Faculty of Life Sciences, University of Copenhagen, Rolighedsvej 21, DK-1958 Frederiksberg C, Denmark b Department of Biological Sciences, University of Aarhus, Building 1137, Universitetsparken, DK-8000 A ˚ rhus C, Denmark Received 9 July 2007; revised 14 September 2007; accepted 13 October 2007 Available online 22 October 2007 Abstract The palm tribe Chamaedoreeae reaches its higher diversity in Central America, however, its distribution ranges from the north eastern part of Mexico to Bolivia with a disjunction to the Mascarene Islands in the Indian Ocean. The disjunct distribution of Chamaedoreeae is generally considered a result of Gondwana vicariance and extinction from Africa and/or Madagascar. However, latitudinal migrations and their role in shaping the distribution of this tribe in the Americas have been largely overlooked. In this study we used seven plastid and two nuclear DNA regions to investigate the phylogenetic relationships and biogeography of the Chamaedoreeae. The resulting phy- logeny fully resolved the generic relationships within the tribe. The exact area of origin of the tribe remains uncertain, but dating analyses indicated an initial diversification of the Chamaedoreeae during the Early Eocene, followed by long distance dispersion to the Mascarene Islands in the late Miocene. The radiation of Hyophorbe could have taking place on islands in the Indian Ocean now submerged, but its former presence in Africa or Madagascar cannot be ruled out. At least two independent migrations between North and South America predating the rise of the Panama isthmus need to be postulated to explain the distribution of Chamaedoreeae, one during the Middle Eocene and a second during the Miocene. Whereas the traditional interpretation of distribution of Chamaedoreeae species assumes a west Gondwana origin of the group, the findings presented in this paper make it equally possible to interpret the group as a primarily boreotropical element. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Antilles; Arecaceae; Boreotropics; Caribbean geology; Central America; Chamaedorea; Dispersal; Gaussia; Gondwana break-up; Hyophorbe; Eocene land bridges; Latitudinal migrations; Mascarene Islands; Neotropics; Panama isthmus; Synechanthus; Wendlandiella; ndhF; matK; trnL-trnF; trnD-trnT; rps16 intron; PRK; RPB2 1. Introduction Explaining disjunct distribution is an important aim of biogeography. Following the 1960s general acceptance of the theory of continental drift, vicariance became the pre- dominant driver in historical biogeography. However, an increasing number of studies using dated phylogenies indi- cate that dispersal and not Gondwana vicariance often has been the driving force shaping the distribution of plant groups in the southern hemisphere (Davis et al., 2002; Muellner et al., 2006; Renner, 2004a; Sanmartı ´n and Ron- quist, 2004; Zerega et al., 2005), although Gondwana vicar- iance still holds in a number of cases (Sytsma et al., 2004). Proposed explanations for these findings include interplate dispersal routes across now submerged land bridges or island chains (Morley and Dick, 2003) or dispersal in sea water or on floating mats of vegetation following ocean currents and predominant wind directions (Renner, 2004a; Zhang et al., 2007). In the palm family, dated phylogenies of the Cocoseae (Gunn, 2004) and the Ceroxyloideae (Tre ´nel et al., 2007) both indicate Eocene trans-oceanic dispersal between America and Africa. These results are also corroborated in a dated phylogeny of the palm subfamilies Ceroxyloideae and Arecoideae presented 1055-7903/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.ympev.2007.10.010 * Corresponding author. Fax: +45 3533 2821. E-mail address: arc@life.ku.dk (A. Cuenca). www.elsevier.com/locate/ympev Available online at www.sciencedirect.com Molecular Phylogenetics and Evolution 46 (2008) 760–775