RV 2123a. Japan, Nagasaki, trawled offshore, 75-100 m. Scale bar is 1 cm.
RV 0563. Japan, Honshu, Aichi Prefecture, Mikawa Province, Mikawa. Scale bar is 1 cm.
The Pliocene Ancilla okawai Yokoyama, 1923, occurring in the same region, seems to be the precursor of the current species. It is extremely similar in shell shape but its operculum is unknown. However, the taxon is here regarded as a junior synonym.