title: Post-Boreotropical dispersals explain the pantropical disjunction in Paederia (Rubiaceae).
abstract: OBJECTIVE
  Pantropical intercontinental disjunction is a common biogeographical pattern in flowering plants exhibiting a discontinuous distribution primarily in tropical Asia, Africa and the Americas. Only a few plant groups with this pattern have been investigated at the generic level with molecular phylogenetic and biogeographical methods. Paederia (Rubiaceae) is a pantropical genus of 31 species of woody lianas, with the greatest species diversity in continental Asia and Madagascar and only two species from tropical America. The aim of this study was to reconstruct the biogeographical history of Paederia based on phylogenetic analyses to explore how the genus attained its pantropical distribution.
  
  
  METHODS
  Maximum parsimony and Bayesian inference were used for phylogenetic analyses using sequences of five plastid markers (the rbcL gene, rps16 intron, trnT-F region, atpB-rbcL spacer and psbA-trnH spacer). Biogeographical inferences were based on a Bayesian uncorrelated lognormal relaxed molecular clock together with both Bayesian and likelihood ancestral area reconstructions.
  
  
  RESULTS
  The data suggest an early diverged Asian lineage sister to the clade of the remaining species consisting of a predominantly Asian sub-clade and a primarily Malagasy sub-clade. Paederia is inferred to have originated in the Oligocene in tropical continental Asia. It then reached Africa in the early to middle Miocene, most probably via long-distance dispersal across the Indian Ocean. The two Neotropical species are inferred to have derived independently in the late Miocene from ancestors of Asia and East Africa, respectively.
  
  
  CONCLUSIONS
  The results demonstrate the importance of post-Boreotropical long-distance dispersals (across three major oceans) in shaping the global pantropical disjunction in some plants, such as Paederia, with small, winged diaspores adapted to long-distance dispersal by various agents including wind, ocean currents or birds. Overland migration is less likely to explain its palaeotropical disjunction between Asia and Africa.
authors.affiliation: Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
authors.forename: Ze-Long
authors.initials: ZL
authors.lastname: Nie
authors.forename: Tao
authors.initials: T
authors.lastname: Deng
authors.forename: Ying
authors.initials: Y
authors.lastname: Meng
authors.forename: Hang
authors.initials: H
authors.lastname: Sun
authors.forename: Jun
authors.initials: J
authors.lastname: Wen
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D044822:Biodiversity; D005075:Biological Evolution; D010802:Phylogeny; D058974:Phylogeography; D018087:Plastids / Q000235:genetics; D019666:Rubiaceae / Q000235:genetics*; D014329:Tropical Climate