The speciation history of northern‐ and southern‐sourced Eranthis (Ranunculaceae) species on the Korean peninsula and surrounding areas

The temporal and spatial origins and evolution of the genus Eranthis have not been previously studied. We investigated the speciation and establishment histories of four Eranthis species: Eranthis byunsanensis, E. pungdoensis, E. stellata, and E. pinnatifida. The sampling localities were Korea, Japan, Jilin in China, and the area near Vladivostok in Primorskiy, Russia. We used 12 chloroplast microsatellite loci (n = 935 individuals) and two chloroplast noncoding regions (rpl16 intron, petL‐psbE intergenic spacer; n = 33 individuals). The genetic diversity, genetic structure, phylogenetic relationships of the four species were analyzed, and their ancestral areas were reconstructed. The high genetic diversity of the Jeju island population of E. byunsanensis and Russian populations of E. stellata indicated these species’ northward and southward dispersal, respectively. The genetic structure analyses suggest that the populations in these four species have limited geographical structure, except for the Chinese E. stellata population (SCP). The phylogenetic analyses suggest that E. byunsanensis and E. pinnatifida are sister species and that Chinese SCP may not belong to E. stellata. The ancestral area reconstruction revealed that the most recent common ancestor of the four species existed in the current Chinese habitat of E. stellata. This study shows that E. byunsanensis and E. pinnatifida originated from a southern Eranthis species and speciated into their current forms near Jeju island and near western regions of Japan, respectively, during the Miocene. E. stellata may have dispersed southward on and near the Korean peninsula, though its specific origin remains unclear. Interestingly, the Chinese E. stellata population SCP suggests that the Chinese population might be most ancient among all the four Eranthis species. E. pungdoensis may have allopatrically speciated from E. byunsanensis during the Holocene. The Korean peninsula and the surrounding areas can be considered interesting regions which provide the opportunity to observe both northern‐ and southern‐sourced Eranthis species.