Isozyme variation in salamanders of the nebulosus-lichenatus complex of the genus Hynobius from eastern Honshu, Japan, with a description of a new species

Isozyme variation was studied in 244 individuals of the Hynobius nebulosus-lichenatus complex from eastern Honshu, between the Kinki and Tohoku Districts, .Japan. Starch gel electrophoresis was used to study variation at 17 loci. Six named species (H. lichenatus, H. nigrescens, H. takedai, H. abei, H. tokyoensis, H. nebulosus) were clearly separated but by relatively low genetic distances (minimum value of Nei's D=0.22), although genetic relationships among these species were largely in disaccord with the currently recognized phylogenetic relationships. The genetic distances between the population from Hakuba and all the named species of this complex proved to be sufficiently high to differentiate the population at a specific rank. On the basis of this result, the population from Hakuba is described as a new species, Hynobius hidamontanus. This species is distributed in the montane region of Nagano Prefecture, in the Hida Mountains of the Chubu District, Central Japan. It belongs to the nebulosus-lichenatus complex of Hynobius, and is characterized by a shallow vomerine teeth series, small number of vomerine teeth, intermediate body shape between H. lichenatus and H. nebulosus, absence of striations on the egg sac envelope, and unique electrophoretic pattern of isozymes.