Dicharax (?) placenovitas (Minato, 1981)
Cipangocharax placenovitas Minato, 1981: 135-137, figs 1-3.
Cipangocharax placenovitas - Azuma 1982: 12-13; Minato 1988: 17, pl. 2, figs 3, 4; Minato 1993: 1, fig. 6.
Type locality.
"Arakura (Limestone region), Haruno-cho, Agawa-gun, Kochi-ken, Japan".
Material examined.
NSMT-Mo 58918 (holotype).
Remarks.
Protoconch low, smooth, but the last 0.5 whorl of the protoconch was slightly weathered; ca. 24 ribs on R2, well separated and wide near beginning of tube, gradually becoming narrower, and dense towards end of tube; near tube ribs situated very close to each other, some of them overlap with their neighbours; ribs clearly separated at edge of body whorl, but spaces still much narrower than a rib width; no spiral lines visible on R1.
Operculum with a big central nipple on its inner side; however, the outer belt was absent. The columellar margin of the aperture is not sinuated. The aperture forms a connection between the Cipangocharax -type and normal-type aperture.