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Abstract: A new species of salamander, Hynobius mikawaensis, is described from the eastern part of Aichi Prefecture, central Japan. It is a lentic breeder of the so-called H. lichenatus species group, and is phylogenetically closest to H. nigrescens and H. takedai. Morphologically, it differs greatly from H. nigrescens, but is very similar to H. takedai, from which it could be differentiated by some morphological traits such as shorter forelimbs and hindlimbs, but longer axilla-groin length, all relative to snout-vent length. The new species from the southern Pacific side of central Japan is completely separated geographically from H. nigrescens and H. takedai, both from the northern, Japan Sea side, by the intervening high mountains. This north/south disjunctive distributional pattern is highly unique among Japanese fauna. The range of the species is so small that immediate measure of conservation is necessary.
Key words: Conservation, Distribution, Hynobius mikawaensis new species, Hynobius takedai, Lentic breeder
Introduction
Small salamanders of the family Hynobiidae Cope, 1859 are highly differentiated within Japan, and each region of the islands is home to its own endemic species. Thus, they are very important for tracing the evolutionary history of Japanese amphibians. Small lenticbreeding salamanders constitute the larger group of Japanese Hynobiidae and all species are regarded as endangered (Ministry of the Environment, 2014). In the past two decades, the presence of several unique salamander species has been reported from Japan (Matsui et al., 2004; Nishikawa and Matsui, 2014), but all of them are lotic breeders. Of the lentic breeders, no new species have been found after H. takedai Matsui and Miyazaki, 1984 and H. hidamontanus Matsui, 1987 were described. Subsequently we found another undescribed species from the region east of the city of Nagoya, Aichi Prefecture, Tokai area of central Japan.
Our molecular as well as morphological comparisons of the populations from eastern Aichi with known congeners proved the populations form a taxon that could be distinguished from all the other species. In this short article, we describe the salamander from eastern Aichi as a new species on the basis of the results of molecular and morphological analyses.
Materials and Methods
DNA analyses
Voucher specimens are stored at the Graduate School of Human and Environmental Studies, Kyoto University (KUHE), Japan. For genetic comparisons, we...