Shell up to 17 mm in length at maturity (holotype), weakly spinose, stout. Spire high with 1,75 protoconch whorls and up to 6 weakly shouldered teleo-conch whorls. Protoconch whorls rounded, smooth, terminal varix eroded. Suture lightly impressed. First teleoconch whorl with 6 axial varices, second with 8, third with 7, fourth with 6, fifth with 5, last teleoconch whorl (holotype) with 4 varices with 5 or 6 short, acute, open spines. Former whorls with shoulder spine and 1 or 2 shorter spines adaperturally. Other axial sculpture consisting of fine growth striae. Spiral sculpture of last teleoconch whorl of 5 or 6 more or less strong cords that connect the varicial spines. Presence of one thread between each pair of cords in the paratype. Former whorls with 2 or 3 spiral cords. Aperture rounded. Columellar lip flaring, smooth, rim erect abapically, adherent adapically. Anal notch shallow, broad. Outer lip broad with 5 strong (holotype) or weak (paratype) denticles within. Siphonal canal medium-sized, straight, open, with 2 small, acute, open spines in the paratype; spines almost obsolete in the holotype. Uniformly light brown.

Muricopsis mbotyiensis n.sp. is different from other species of Muricopsis s.s. in its rounded aperture with broad outer lip and arrangement of denticles within. Muricopsis (Murexsul) cuspidatus (Sowerby. 1879) from New Caledonia is somewhat similar but has a more ovate aperture with narrow outer lip and a different arrangement of denticles, a comparatively larger shell with narrower, and (typical for the subgenus Murexsul) more spinose varices.