title: Niche evolution through time and across continents: The story of Neotropical Cedrela (Meliaceae).
abstract: OBJECTIVE
  Climatic and geological changes have been considered as major drivers of biological diversification. However, it has been generally assumed that lineages retain common environmental affinities, suggesting a limited capacity to switch their climatic niche. We tested this assumption with a study of the evolution of climatic niches in the Neotropical tree genus Cedrela (Meliaceae). •
  
  
  METHODS
  We combined distribution models of extant Cedrela with a dated molecular phylogeny based on one nuclear (ITS) and three plastid markers (psbA-trnH, trnS-G and psbB-T-N) to reconstruct the evolutionary dynamics of climatic niches. We calculated relative disparity of climatic tolerances over time to test for niche evolution within subclades or divergence between subclades and conservatism among closely related groups. Published fossil records and studies on paleosols were evaluated for the distribution and climatic conditions of extinct Cedrela. •
  
  
  RESULTS
  The fossil record of Cedrela suggested a major biome shift from paratropical conditions into warm-temperate seasonal climates in the Early Oligocene of western North America. In the Miocene, Cedrela extended from North America (John Day Formation, Oregon, USA) to southern Central America (Gatún, Panama). Diversification in the early evolutionary history was mainly driven by changes in precipitation. Temperature had an increasing impact on ecological diversification of the genus from the Miocene onwards. Sister-species comparisons revealed that recent speciation events may be related to divergence of climatic tolerances. •
  
  
  CONCLUSIONS
  Our study highlights the complexity of climatic niche dynamics, and shows how conservatism and evolution have acted on different temporal scales and climatic parameters in Cedrela.
authors.affiliation: Biodiversity and Climate Research Centre (BiK-F) & Senckenberg Gesellschaft für Naturforschung, Department of Botany and Molecular Evolution, Grunelius-Moellgaard Laboratory, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.
authors.forename: A Valerie
authors.initials: AV
authors.lastname: Koecke
authors.forename: Alexandra N
authors.initials: AN
authors.lastname: Muellner-Riehl
authors.forename: Terence D
authors.initials: TD
authors.lastname: Pennington
authors.forename: Gertrud
authors.initials: G
authors.lastname: Schorr
authors.forename: Jan
authors.initials: J
authors.lastname: Schnitzler
mesh_terms: D001483:Base Sequence; D031587:Cedrela / Q000235:genetics*; D002489:Central America; D002980:Climate; D021901:DNA, Intergenic / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D005580:Fossils; D049810:Genetic Speciation; D008969:Molecular Sequence Data; D010802:Phylogeny; D018087:Plastids / Q000235:genetics; D017422:Sequence Analysis, DNA; D013020:South America; D013045:Species Specificity; D013997:Time Factors
chemical_list: D021901:DNA, Intergenic; D018744:DNA, Plant
keywords: Cedrela; Eocene; Meliaceae; Miocene; Oligocene; ancestral niche; climatic niche modeling; fossil; relative disparity