We describe a new species of polyclad flatworm, Phaenoplana kopepe sp. nov., from Chichijima island in the Ogasawara Islands, Japan. This is the first report of Phaenoplana from Japan. Phaenoplana kopepe sp. nov. is characterized by i) a vagina that curves anteriorly, ii) gonopores well-separated from each other, and iii) a Lang’s duct that is shorter than the vagina. We provide a partial sequence (610 bp) from the mitochondrial cytochrome c oxidase subunit I gene as a DNA barcode for the species.

A specimen (114.4 mm SL) of the rare ophidiid species, Benthocometes australiensis Nielsen, 2010, was collected from a deep-sea water intake at a depth of 320 m off Cape Muroto, Kochi Prefecture, Shikoku Island, Japan. The species is previously only known from the holotype trawled off northwestern Australia. Thus, the present specimen is the first record from the Northern Hemisphere and the second record of the species. New Japanese names “Suisei-ashiro-zoku” and “Muroto-suisei-ashiro” are proposed for Benthocometes and B. australiensis respectively.