The biogeographical history of the cosmopolitan genus Ranunculus L. (Ranunculaceae) in the temperate to meridional zones

Ranunculus is distributed in all continents and especially species-rich in the meridional and temperate zones. To reconstruct the biogeographical history of the genus, a molecular phylogenetic analysis of the genus based on nuclear and chloroplast DNA sequences has been carried out. Results of biogeographical analyses (DIVA, Lagrange, Mesquite) combined with molecular dating suggest multiple colonizations of all continents and disjunctions between the northern and the southern hemisphere. Dispersals between continents must have occurred via migration over land bridges, or via transoceanic long-distance dispersal, which is also inferred from island endemism. In southern Eurasia, isolation of the western Mediterranean and the Caucasus region during the Messinian was followed by range expansions and speciation in both areas. In the Pliocene and Pleistocene, radiations happened independently in the summer-dry western Mediterranean-Macaronesian and in the eastern Mediterranean-Irano-Turanian regions, with three independent shifts to alpine humid climates in the Alps and in the Himalayas. The cosmopolitan distribution of Ranunculus is caused by transoceanic and intracontinental dispersal, followed by regional adaptive radiations.