Diagnosis: Shell moderately small (12-20 mm), claviform with low spire (often decollated in adult), papilliform apex, relatively small aperture and short base, with a moderately strong fasciole; siphonal canal short, wide, its termination deeply notched, square-set; parietal pad large, angular, with somewhat lamellar growth-lines, constricting anal sinus; anal sinus moderately deep, narrowly and roundly U-shaped. its opening (in adult) greatly constricted and usually directed slightly abapically; stromboid notch weak; whorls usually shouldered, without a distinct subsutural cord (although sometimes slightly swollen below suture), axial ribs weak to strong, typically broad and shouldered, crossed by low spiral threads; sometimes with a prelabral varix; colour drab. Protoconch subcylindrical, blunt, of 2-2,5 whorls, smooth except for weak axial riblets (and sometimes spiral striae) on last half-whorl. Operculum oblanceolate with acute apex, nucleus terminal. Radula crassispirine, of marginal plates only, shaft short, cutting edge not sharply defined, accessory limb fairly short, inserted into socket on underside of plate.
Notes: Nquma is allied to the extensive American genus Crassispira Swainson, 1840. which, however, contains large to medium-sized species, with a distinct to massive subsutural cord, an openly U-shaped anal sinus, a protoconch with well-developed axial riblets on its last whorl, and a dark brown to black ground colour, sometimes with a dark periostracum. None of the Western Hemisphere species appear to be naturally decollated, although this is characteristic of several West African species (callosa Kiener, 1841, carbonaria Reeve, 1843) which are sometimes referred to Crassispira. From Buchema Nquma differs in lacking a subsutural cord, and in its weak spiral sculpture and greatly constricted anal sinus (which resembles the Greek upper case letter omega).