title: Key innovations and climatic niche divergence as drivers of diversification in subtropical Gentianinae in southeastern and eastern Asia.
abstract: Geological and climatic changes associated with the uplift of the Qinghai-Tibet Plateau (QTP) have been suggested as drivers for biological diversification locally and in neighboring regions. To test this hypothesis, we investigated the niche evolution of Tripterospermum (Gentianaceae) and related Asian genera through time.
  
  
  
  We conducted Species Distribution Modeling using Maximum Entropy Modeling (MaxEnt). Furthermore, we performed stochastic character mapping and produced disparity-through-time plots, and examined putative key innovations using the binary state speciation and extinction approach (BISSE).
  
  
  
  Kuepferia and Sinogentiana prefer the coolest and driest habitat, having rather conserved niches. Despite a tendency for niche evolution, Crawfurdia and Metagentiana are probably restricted to a narrow distribution range because of their poor dispersal ability. In contrast, Tripterospermum has the broadest niche and occurs under the warmest and wettest conditions. A higher degree of niche evolution and a more efficient dispersal mechanism allowed this genus to diversify more and occupy a broader distribution range.
  
  
  
  The QTP genera producing dry capsules, whether displaying niche conservatism (Kuepferia and Sinogentiana) or a tendency for niche evolution (Crawfurdia and Metagentiana), are less species-rich and have a more restricted distribution than Tripterospermum (stronger niche evolution and berry-like fruits). The evolution of berry-like fruits corresponds to increased speciation rates, and could therefore be viewed as a key innovation. In contrast to the majority of studies on plants occurring around the QTP, we find that speciation was probably mediated by niche breadth and dispersal ability rather than geophysical changes.
authors.affiliation: Leipzig University, Institute of Biology, Department of Molecular Evolution and Plant Systematics & Herbarium Lipsiense (LZ), Johannisallee 21-23, D-04103 Leipzig, Germany Goethe University, Institute for Ecology, Evolution and Diversity, Max-von-Laue-Str. 13, D-60439 Frankfurt/Main, Germany Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Matuszak
authors.affiliation: Leipzig University, Institute of Biology, Department of Molecular Evolution and Plant Systematics & Herbarium Lipsiense (LZ), Johannisallee 21-23, D-04103 Leipzig, Germany adrien.favre@uni-leipzig.de.
authors.forename: Adrien
authors.initials: A
authors.lastname: Favre
authors.affiliation: Leipzig University, Institute of Biology, Department of Molecular Evolution and Plant Systematics & Herbarium Lipsiense (LZ), Johannisallee 21-23, D-04103 Leipzig, Germany Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Schnitzler
authors.affiliation: Leipzig University, Institute of Biology, Department of Molecular Evolution and Plant Systematics & Herbarium Lipsiense (LZ), Johannisallee 21-23, D-04103 Leipzig, Germany German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.
authors.forename: Alexandra N
authors.initials: AN
authors.lastname: Muellner-Riehl
mesh_terms: D000531:Altitude; D001210:Asia, Southeastern; D044822:Biodiversity; D005075:Biological Evolution; D019277:Entropy; D005202:Asia, Eastern; D029965:Gentianaceae / Q000502:physiology*; D005843:Geography; D008962:Models, Theoretical; D010802:Phylogeny; D019655:Quantitative Trait, Heritable; D014329:Tropical Climate
keywords: Gentianaceae; Qinghai-Tibet Plateau; Tripterospermum; climatic niche; disparification through time; niche evolution; species distribution modeling; stochastic character mapping