Phylogeographic History of Endangered Hokuriku Salamander, Hynobius takedai (Amphibia: Caudata)

Knowledge of the phylogeographic history of organisms is valuable for understanding their evolutionary processes. To the best of our knowledge, the phylogeographic structure of Hokuriku salamander, Hynobius takedai, an endangered species, remains unclear. This study aimed to elucidate the phylogeographic history of H. takedai, which is expected to be strongly influenced by paleogeographic events. Phylogenetic analysis based on partial sequences of the mitochondrial DNA cytochrome b gene confirmed the genetic independence of H. takedai, and the divergence time with closely related species was estimated to be from the Late Pliocene to the Early Pleistocene. In the phylogenetic tree, two clades were identified within H. takedai, and their haplotypes were found in samples collected from the west and east of the distribution range. These intraspecific divergences were strongly influenced by geohistorical subdivisions of the current major distribution areas in the Middle Pleistocene. One clade was further subdivided and its formation may have been influenced by sea level changes in the Late Pleistocene.