Two new temporary ectoparasitic isopods (Cymothoida: Cymothooidea) from Korean waters with a note on geographical distributions of Leach, 1818 and Leach, 1814.

Two new species of temporary ectoparasitic isopods, and , are reported from the southern Islands of the Korean Peninsula. is distinguishable from its related species by the following characteristics: (1) laterally stepped rostrum; (2) separated eyes; (3) propodal blade having eight robust setae; and (4) merus having four or five blunt robust setae in pereopods 1-3. differs from its congeners by the combination of the following characteristics: (1) body covered with numerous tubercles and setae, (2) cephalon having tooth-like paraocular ornamentations; and (3) frontal border having two inferior frontolateral processes. These two new species are the 13 species and 19 species in the temperate Northern Pacific region, respectively. Discovery of these new species represents high species diversity of the genera Leach, 1818 and Leach, 1814 worldwide as well as in the Northern Pacific region. In addition, faunal diversity analysis on the members of both genera revealed that species show high-latitude diversity whereas species have low-latitude diversity.