Taxonomic study on the photid amphipods (Senticaudata, Corophiida, Photoidea, Photidae) from Korean waters, with descriptions of a new genus and seven new species

Abstract. In this paper, seven new species of the family Photidae from Korean waters are described and illustrated in detail. Among them, Exiliphotis petilasp. nov. is a monotype of the newly reported Exiliphotisgen. nov., which is characterized by slenderer and more elongate pereopods 5–7 than those of other genera of the family Photidae. The genus Latigammaropsis is reported for the first time from Korean waters based on the description of Latigammaropsis careocavatasp. nov., which is differentiated from other Gammaropsis group by having weakly sexual dimorphic gnathopods 2, those have simple palmar margins in both sexes. Three new species of Photis are also described: Photis broncasp. nov., Photis posterolobussp. nov., and Photis longicarpussp. nov. The formerly misidentified Photis longicaudata from Japan and China as well as the Korean material could be classified as a new species, P. broncasp. nov. For that, the syntypes of P. longicaudata were re-examined, and lectotype and paralectotypes were newly designated in this study. Photis broncasp. nov. is characterized by quadrate tooth on the palmar margin medially on gnathopod 2 in both sexes. Photis posterolobussp. nov. shows a pointed posterior lobe on the ischium and a well-developed process of the propodus on male gnathopod 2. Photis longicarpussp. nov. can be distinguished from other species of the genus by very elongate carpus of male gnathopod 1. Two new species belonging to the genus Podoceropsis are also reported: Podoceropsis insinuomanussp. nov. has a strongly bisinuous palmar margin on male gnathopod 2, and Podoceropsis pseudoclavapessp. nov. differs from the closely related species of Podoceropsis clavapes by different shape of the palmar margin and shorter dactylus of male gnathopod 2. Additionally, a key to the Korean species of Photidae is provided.