The palaeonemertean genus Tubulanus Renier, 1804 currently harbors 35 species inhabiting the intertidal to the hadal zones. During a faunal survey in Sagami Bay, Japan, a single specimen of undescribed tubulanid having uniformly pale-colored body with a single dark-colored stripe on the dorsal surface was collected by dredging at depths of 116-211 m. Based on the body coloration and some anatomical features, it can be differentiated from the 35 congeners and is thus described herein as Tubulanus misakiensis sp. nov. In a molecular phylogenetic tree constructed with sequences available in public databases representing five markers (16S rRNA, cytochrome c oxidase subunit I [COI], 18S rRNA, 28S rRNA [not obtained for T. misakiensis], and histone H3), T. misakiensis was sister to Tubulanus izuensis Hookabe, Asai, Nakano, Kimura and Kajihara, 2020 and nested within a clade along with seven unidentified specimens from the abyssal and hadal zones (3428-9577 m); T. misakiensis and T. izuensis differed by 11.7% uncorrected p-distance in terms of 657-bp COI sequences.
Keywords: bathyal; deep sea; marine invertebrates; ribbon worm; systematics.