Differentiation of golden-ringed dragonfly Anotogaster sieboldii (Selys, 1854) (Cordulegastridae: Odonata) in the insular East Asia revealed by the mitochondrial gene genealogy with taxonomic implications

Molecular phylogeographical analyses of Anotogaster sieboldii (Selys, 1854) were conducted to reveal the differentiation process of insular populations. The gene genealogy based on 845 bp of the mitochondrial genes (cytochrome oxidase subunit I and subunit II) indicated that A. sieboldii includes two deeply separated lineages. These two major lineages seem to have differentiated in Miocene before the formation of the insular East Asia. One lineage includes three inner clades that correspond to the populations of northern area (the Japanese main islands, Korean Peninsula, Yakushima), Amamioshima and Okinawajima. Populations of Central Ryukyu, including Amamioshima and Okinawajima, might have been divided from the northern populations in early Pleistocene. The other major lineage includes populations of the Yaeyama Group, Taiwan and East China. The former two populations were reconstructed as a reciprocal monophyletic group. Populations of Taiwan and Yaeyama Groups would have been separated from the continental ones in Pleistocene. These two highly divergent lineages should be recognized as distinct species. Furthermore, the mitochondrial lineages revealed six genetically distinct and geographically isolated assemblages: (1) northern populations, (2) Amamioshima, (3) Okinawajima, (4) Yaeyama Group, (5) Taiwan and (6) East China.