title: The biogeographic origin of a radiation of trees in Madagascar: implications for the assembly of a tropical forest biome.
abstract: BACKGROUND
  Madagascar's rain forests are characterized by extreme and uneven patterns of species richness and endemicity, the biogeographic and evolutionary origins of which are poorly understood.
  
  
  METHODS
  Here we use a time-calibrated phylogeny of a dominant group of trees in Madagascar's eastern rain forests, Canarium, and related Burseraceae (Canarieae), to test biogeographic hypotheses regarding the origin and radiation of the flora of this unique biome.
  
  
  RESULTS
  Our findings strongly support the monophyly of Malagasy Canarium, suggesting that this clade represents a previously undocumented in situ radiation. Contrary to expectations of dispersal from Africa during the Oligocene, concurrent with the formation of Madagascar's rain forest biome, our analyses support a late Miocene origin for Malagasy Canarium, probably by long distance dispersal from Southeast Asia.
  
  
  CONCLUSIONS
  Our study illustrates the importance of considering long distance dispersal as a viable explanation for clades with pantropical distributions diversifying subsequent to the Oligocene, and it highlights the formation of the Indo-Australian Archipelago and associated fast-moving equatorial surface currents, suggesting an under-appreciated evolutionary link among tropical centers of endemism.
  
  
  CONCLUSIONS
  We postulate that the relatively recent establishment and radiation of Canarium in Madagascar may have been facilitated by the highly stochastic climates associated with these forest ecosystems.
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, P.O. Box 208106, New Haven, CT, 06520, USA. sarah.federman@yale.edu.
authors.forename: Sarah
authors.initials: S
authors.lastname: Federman
authors.affiliation: North Carolina Museum of Natural Sciences, Raleigh, NC, 27601, USA. alex.dornburg@naturalsciences.org.
authors.forename: Alex
authors.initials: A
authors.lastname: Dornburg
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, P.O. Box 208106, New Haven, CT, 06520, USA. alexander.downie@yale.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Downie
authors.affiliation: Department of Anthropology, Yale University, 51 Hillhouse Avenue, New Haven, CT, 06520, USA. alison.richard@yale.edu.
authors.forename: Alison F
authors.initials: AF
authors.lastname: Richard
authors.affiliation: New York Botanical Garden, Institute of Systematic Botany, 2900 Southern Boulevard, Bronx, NY, 10458, USA. ddaly@nybg.org.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Daly
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, P.O. Box 208106, New Haven, CT, 06520, USA. michael.donoghue@yale.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Donoghue
mesh_terms: D005075:Biological Evolution; D002980:Climate; D017753:Ecosystem; D019143:Evolution, Molecular; D065928:Forests; D008270:Madagascar; D010802:Phylogeny; D014197:Trees / Q000145:classification*