A new species of the genus Melita (Crustacea, Amphipoda, Melitidae) and a new record for Melita shimizui from Korean Brackish Waters

Two melitid amphipod species belonging to the genus Melita were collected from Korean brackish waters, with one of species is new and is described as Melita aestuarina. The new species was identified as the dominant species in the Korean brackish water region, yet its morphological characteristics had not been studied until now. The morphology of the propodus of gnathopod 2 elongate-ovate and outer ramus of uropod 3 about 9 times longer than wide, are the major characteristics which differentiate the new species from its congeners. Additionally, nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) of M. aestuarina sp. nov. support divergence at the species level. The other species, Melita shimizui was previously known from Chinese and Japanese waters. It exhibits similarities with M. choshigawaensis and M. setiflagella. However, M. shimizui can be obviously distinguished by having linear outer ramus of uropod 3, which is distinct from M. choshigawaensis and weakly setose antenna 2, which is distinct from M. setiflagella. Both species are illustrated and compared to related species and a key is also provided to the species of genus Melita from Korea.