Allozymic variation and phylogeography of two genetic types of onychodactylus japonicus (Amphibia: Caudata: Hynobiidae) sympatric in the Kinki District, Japan

On the basis of allozyme and mtDNA sequence variation, we elucidated genetic relationships between two sympatric genetic types of Onychodactylus japonicus in Kinki and adjacent districts, and investigated their phylogeography. Allozymic analysis revealed the presence of two distinct genetic types (the SW-Honshu and Kinki groups) in this area, and their sympatric occurrence in three of 10 sampling sites. Fixed or nearly fixed allele differences in several loci strongly suggested reproductive isolation between the two types, although one hybrid specimen was found in a locality. Analyses of mtDNA using 194 specimens from 22 localities also demonstrated two genetic types. From phylogeographic and population genetic analyses, it was surmised that these two types diverged allopatrically, and secondarily contacted to become sympatric by the Pleistocene uplift of mountains. Our results indicate different specific status for these two types and separation of the Kinki group from O. japonicus, to which the SW-Honshu group belongs.