Although plethodontid salamanders comprise seventy percent of salamander species worldwide, Karsenia koreana is the first member of this taxon known from Asia. Like other plethodontids, it lacks lungs and breathes through its moist skin.
Cladistic analysis using Bayesian analysis of molecular data places Karsenia koreana as sister group to the clade containing Aneides and the desmognathine salamanders. This implies that plethodontid salamanders may have had a worldwide range 60 to 100 million years ago. As the global climate cooled, New World taxa thrived while Old World populations declined. Other plants and animals currently found in Asia and North America share close relationships, showing a similar pattern of biogeography.