Unidentia nihonrossija sp. n. Japan, Pacific Honshu, Osezaki. ZMMU Op-517, specimen 4.5 mm in length (fixed): A dorsal view (live) B lateral view (live) C ventral view (live) D details of cerata (live) E particular elongate elevations at the base of cerata (fixed) F jaw, SEM G details of masticatory process of jaw, SEM H details of masticatory process of jaw, light microscopy I radular teeth, posterior part, SEM J reproductive system, light microscopy. Abbreviations: a anus am ampulla cre ceratal elevated rows fgm female gland mass ps penial sheath pvd prostatic vas deferens rsp proximal receptaculum seminis. Scale bars: F = 100 μm; G, I = 10 μm. Photos and SEM images by T.A. Korshunova, A.V. Martynov.