A new genus and species of Apseudomorpha (Crustacea: Tanaidacea) from the Mar del Plata submarine Canyon, South West Atlantic, and replacement of the preoccupied name Hoplomachus Gutu 2002

A new apseudomorph tanaidacean, Deidamiapseudes poseidon n. gen., n. sp., is fully described and illustrated based on many specimens collected in the Mar del Plata Submarine Canyon, South West Atlantic, at 1144 m depth. The new genus Deidamiapseudes is closely related to the genus Hoplomachus GuA u pound, 2002, from which it can be distinguished by the lack of ommatidia, and by having antennule accessory flagellum of three articles, antenna with small scale, and pleopods with a few setae. In addition, Deidamiapseudes poseidon n. gen., n. sp. was found in deep-sea waters, whereas Hoplomachus is a shallow water genus. The uncertain family position of these two genera is discussed. The name Hoplomachus GuA u pound, 2002, preoccupied by Hoplomachus Fieber, 1858, is replaced with the name Hoplopolemius.