A new genus and two new species of Idoteidae Samouelle, 1819 (Malacostraca: Isopoda: Valvifera) from South Korea, with a key to the genera of Idoteidae

We describe Koridotea hoonsooi, a new genus and new species of Idoteidae Samouelle, 1819 based on specimens collected using light traps in a sedimentary bottom of sand with seaweeds at 1–10 m depth from the southern coast of South Korea. The new genus is distinguished from other idoteid genera by the following combination of characters: pleonite 1 indicated by completely dorsal sutures, pleonites 2 and 3 with ventrolateral sutures only (pleotelsonic formula 1 + 2); maxillipedal palp articles 2 and 3 fused; coxae 2–7 without dorsal coxal plates; pereionite 7 without ventral W-shaped ridge; and pereiopods without spiniform setae on the palm of the propodus. We describe Synidotea wonkimi, a new species based on specimens collected using light traps in a sedimentary bottom of organic-rich mud with seaweeds at 3–7 m depth from the western coast of South Korea. This new species is distinguished from other congeneric species by the following combination of characters: dorsal surface of the body with minute tubercles; head with a single distinct median tubercle and frontal margin deeply concave; and apex of pleotelson with a rounded margin. We provide a key to the genera of Idoteidae and present the partial sequences of the mitochondrial cytochrome c oxidase subunit I (CO1) gene from the two new species. In addition, we discuss the heterogeneous genera of Idoteidae, which aims to eventually establish more precise diagnoses of the idoteid genera.