Historical biogeography of the Angelica group (Apiaceae tribe Selineae) inferred from analyses of nrDNA and cpDNA sequences

Biogeographical patterns and diversification processes of Asia-centered angiosperm groups have been significantly affected by the multistage uplift of the Himalayas-Tibetan Plateau since the Late Tertiary. The divergence time of the largely East Asian Angelica group (Apiaceae, subfamily Apioideae, tribe Selineae) was initially analyzed using BEAST and nrDNA internal transcribed spacer sequence data from 96 representatives of tribe Selineae and relatives. Further analyses of the biogeographical history of the Angelica group were carried out using BEAST, S-DIVA, RASP, and LAGRANGE on datasets containing all or some of the following loci: nrDNA internal and external transcribed spacers; cpDNA rps16 intron; and cpDNA rps16-trnK, rpl32-trnL, and trnL-trnT intergenic spacers. The results suggested that the Angelica group was originally present in the East Palearctic during the global cooling of the late Middle Miocene (13.6 Mya) and that the Angelica s.s. clade originated in the same region at 10.2 Mya. Subsequent diversifications of the Angelica s.s. clade intensified in the East Palearctic during the middle Late Miocene (10.0-7.0 Mya) and in the eastern Himalayan Zone during the late Pliocene and Pleistocene (<4.0 Mya). These diversifications likely corresponded with plateau uplift-driven climatic changes. Considering elevational reconstructions, the differential responses to altitude appear to be the primary factor explaining the recent radiation of the group in the eastern Himalayas. The North American species of the Angelica group were retrieved as polyphyletic and their migrations involved six independent dispersals to North America at least since the middle Late Miocene, including four times from northeast Asia and twice from Europe.