Two new brackish species of the genus Melita Leach, 1814 (Crustacea: Amphipoda: Melitidae) from western Japan

Abstract

Two new species of melitid amphipods are described from brackish waters in Nagasaki and Kagawa Prefectures, Japan: Melita ignis sp. nov. from the Kanahama River, Nagasaki, and Melita latens sp. nov. from the Umayado River, Kagawa. Morphological observation reveals that M. ignis sp. nov. is most similar to M. ogasawaraensis ; however, this new species can be distinguished from the latter by the shape of female coxa 6, male mandible, and telson. Melita latens sp. nov. resembles M. shimizui , but differs from M. shimizui by the structures of male gnathopod 2, pereopod 7 merus, and telson. In addition, molecular phylogenetic analysis based on the nuclear and mitochondrial DNA sequences showed that M. ignis sp. nov. clusters with M. ogasawaraensis , and M. latens sp. nov. is a sister taxon of a clade comprising M. aestuarina, M. choushigawaensi, M. nunomurai, M. okinawaensis , and M. shimizi .