A New Species of Free-living Marine Nematode, Proplatycoma tsukubae sp. nov. (Enoplida: Leptosomatidae), from Japan

Abstract

A new species of free-living marine nematode, Proplatycoma tsukubae sp. nov. (Enoplida: Leptosomatidae: Platycominae), is described from Japan. The specimens were obtained from sea-floor sediments collected at a depth of 117–202 m off the coast of Shimoda, Shizuoka Prefecture, Japan. Proplatycoma tsukubae sp. nov. is similar to P. africana (Gerlach, 1959) in the unilobed amphidial flaps. However, it differs from P. africana based on the much shorter amphidial flaps just reaching the anterior edge of the amphidial aperture, the accessory structure of the spicules being constricted at the middle and tapering toward both ends, the longer apophyses of the gubernaculum, and the blunt tip of the tail. The partial nucleotide sequences for the cytochrome c oxidase subunit I and the 18S rRNA regions in P. tsukubae sp. nov. are also presented for future applications in DNA barcoding or phylogenetic studies. Updated taxonomic keys to genera in the subfamily Platycominae and species in Proplatycoma are provided.