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Published: 2022-07-21

Taxonomic reappraisal of Hynobius tokyoensis, with description of a new species from northeastern Honshu, Japan (Amphibia: Caudata)

Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Kyoto, 606-8501 JAPAN
Civil Engineering and Eco-Technology Consultants, Osaka Branch, Minami-senba 1-15-14, Chuo-ku, Osaka 542-0081, JAPAN
Department of Zoology, National Museum of Nature and Science, Tokyo, Amakubo 4–1–1, Tsukuba, Ibaraki 305–0005, JAPAN
Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Niho. Graduate School of Global Environmental Studies, Kyoto University, Yoshida-Honmachi, Kyoto, 606-8501 JAPAN nmatsu-cho, Kyoto, 606-8501 JAPAN
Amphibia eastern Japan new Hynobius nuDNA phylogeny taxonomy Urodela


Previous phylogenetic studies based on mitochondrial DNA data have consistently suggested that Hynobius tokyoensis consists of two major clades, clade A (northern clade) and clade B (southern clade). In this study, we newly estimated their population genetic structure and phylogenetic relationships by nuclear SNPs, and the results suggested heterospecific relationships of the two mitochondrial clades, without present hybridization in between. They were also recognized as morphologically different. The type locality of H. tokyoensis is in Tokyo Prefecture, and therefore clade B corresponds to H. tokyoensis sensu stricto, leaving clade A without available scientific name. We, thus, describe the clade A from northeastern Kanto to southern Tohoku as a new species Hynobius sengokui. The new species is distinguished from H. tokyoensis by its relatively longer axilla-groin distance, shorter trunk, and deeper vomerine teeth series, and is estimated to have diverged from it during the late Pliocene.



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