Shell small for the genus, up to 8.95 mm in length at maturity (holotype), slender, lanceolate, heavy, nodose. Spire very high with 1.40-1.45 protoconch whorls, up to 5 narrow, strongly shouldered, nodose teleoconch whorls; suture impressed. Protoconch small, shouldered, whorls carinate, with a strong, single keel adapically; terminal varix delicate, thin, weakly erect, very weakly curved. Axial sculpture of teleoconch whorls consisting of high, strong, broad, rounded, nodose ribs: eight on first to fourth whorls; six on last whorl. Spiral sculpture of strong high cords, decreasing in strength and height on abapical whorls: IP, P1-P3 visible on whorls 1 to 4 (holotype) or on whorls 1 to 3 (paratype coll. R. Houart), whorl 4 with visible IP, PI, s1, P2, P3; last whorl with IP split, PI, s1, P2, s2, P3, s3, P4, s4, P5, P6, ADP, MP; cords more strongly developed at intersection with axial ribs; P1-P3 low, broad, P4 and P5 high, strong; P4-P6 giving rise to small spinelets on axial ribs. Additional spiral sculpture consisting of numerous, small striae. Juvenile with small, almost indistinguishable IP, P1-P6, ADP, MP; P2 and P3 largest and strongest, P5 weakest. Aperture small, ovate; columellar lip broad, smooth, rim partially erect, adherent at adapical extremity; anal notch broad, deep; outer lip weakly erect, crenulate, with strong narrow rounded denticles of similar size within (ID, D1-D5). Siphonal canal short, broad, weakly recurved dorsally, narrowly open, with ADP and MP narrow, ending as small short spinelets on axial ribs.
Beige or light ochre with brown band at shoulder, between P4 and P5, and P5 and P6; crest of axial ribs light brown (paratype) or yellow-ochre (holotype); aperture glossy white with light brown or yellowish patches.
Operculum light brown, ovate, terminal nucleus surrounded by 15 or 16 concentric ridges. Radula not examined.

. The Muricopsis-like species from West Africa have been included in Risomurex by Vokes & Houart (1986a, 1986b). by Houart (1987, 1990, 1993, 1994 and 19%) and by Rolan & Fernandes (1991). However, in a paper studying the shell morphology in Muricopsinae, Merle et al. (in prep.) show that the West African species are closer to Muricopsis s.s. than they are to Risomurex. Risomurex Olsson & Macginty, 1958 with four or five living species which are all confined to the Western Atlantic is slightly different in having a broader last teleoconch whorl, a lower spire, and broad axial ribs. Muricopsis haidari n. sp. is sympatric with M fusiformis fusiformis (Gmelin. 1791) and M. seminolensis Vokes & Houart. 1986. M haidari is very different from M fusiformis fusiformis and does not need to be compared here. It differs from M, seminolensis in being smaller, more slender, in having lower and broader primary spiral cords, fewer or absent secondary spiral cords, narrower axial ribs, and a higher last teleoconch whorl. It differs from M. rutilus rutilus (Reeve, 1846) from Ghana and M rutilus mariangelae Rolan & Fernandes. 1991 from Sao Tome, in having a smaller shell with more shouldered whorls, broader and lower primary spiral cords, and an aperture with non-fused Dl and D2 (fused in both M rutilus rutilus and M. rutilus mariangelae).

Type material. Senegal, Cap Vert, Dakar, Gouyeteni M'both. October 2002. 14°36’39” N, 17°26'21” W. basalt, 27 m. holotype and 1 juvenile paratype MNHN (lv.); Cap Vert, Dakar.
Distribution. Presently known only from the type material, living at 27-32 m.