Original Description of Rimella rugostoma by Johnson, 1899, p. 79:
- "Shell subfusiform, whorls eight, slightly convex, the two apical whorls smooth, the others beautifully reticulated as follow: The three spiral whorls below the smooth apical whorls, have seven equidistant, flat, revolving ridges, which are crossed by small interrupted longitudinal ribs, obsolete on the upper of the three whorls. The body whorl above the periphery and the first and second spiral whorls have revolving ridges that are divided by a small groove into five pairs, on the body whorl below the periphery are twenty single revolving ridges, which become gradually small toward the base, just above the suture one of the single revolving ridges is also exposed on the first and second spiral whorls; longitudinal ribs prominent, about twenty to each whorl, becoming nodulose where they cross the revolving ridges. Aperture narrow, ovate, outer lip thick, and deeply notched, lobe acute, inner margin crenulated by about twenty short ridges; inner lip thin, expanded, bearing a rugose callous ridge which curves gradually downward toward the posterior end of the aperture, above which, at the posterior commissure is a small rugose triangle, the posterior canal extending to the base of the fourth spiral whorl. Length 20 mm., greatest diam. 9 mm.
Locus typicus: Jackson, Mississippi, USA
Stratum typicum: Eocene
Rimella rugostoma Johnson, 1899, pl. II, fig. 10