Molecular Phylogenetic and Morphological Problems of the Aki Salamander Hynobius akiensis: Description of Two New Species from Chugoku, Japan

Abstract

Two new species of the genus Hynobius are described from the southern part of Hiroshima Prefecture, Japan. Hynobius akiensis was divided into three groups (Hiroshima-Ehime group, Higashihiroshima group, Northern Hiroshima group) based on morphological and molecular analyses; thus, the Hiroshima-Ehime and Higashihiroshima groups were described as Hynobius geiyoensis sp. nov. and Hynobius sumidai sp. nov., respectively. According to morphological comparisons, males of H. geiyoensis sp. nov. have significantly larger snout–vent length relative to those of males of the other two species, whereas members of H. sumidai sp. nov., unlike H. akinesis, have a distinct brownish–yellow stripe on the dorsal side of their tail. Following this description, the distribution area of H. akiensis has changed substantially; thus, the habitat status of this species or two new species should be reassessed for its conservation.