Shell fusiform elongate and solid with a high spire. Protoconch of a little more than one smooth and shiny light brown whorl with a diameter of about 700 mu. Teleoconch of the holotype with 6+ whorls, which exhibit prominent axial ribs that are a little opisthocline in shape, which begin (except on the first two whorls) below a subsutural depressed area, finishing on the lower suture; on the last whorl the ribs fade below the periphery. Last whorl represents 40% of the total shell height, but in juvenile specimens the ratio can reach 50%; spiral sculpture of numerous small but prominent threads which continue up to the base. Aperture oval elongate, siphonal canal short and wide. Background colouration cream or light brown, with a narrow dark band on the suture; below this are irregularly spaced isolated oblique lines; on the last whorl there is a cream band encompassing the widest part of the shell, bordered below by irregular but bold dark brown staining; the lower base is lighter and flecked with lighter and darker weak tubercules. Dimensions: The holotype is 11.6 mm; the paratypes are smaller.
Operculum: Elongated with a terminal nucleus.

Many of the other West African species are larger and wider and can easily be separated from the present species by the decollate spire. We comment on some simi-larly sized species from the area as follows:
- Drillia tripter (von Maltzan, 1883) is the closest species at first glance, however it is generally larger as already indicated, reaching more than 20 mm; it is also endemic to the area of Dakar and bears an elongate operculum with a terminal nucleus. The protoconch of D. tripter is brown/mauve, depressed, bearing more numerous axial ribs on the teleconch and final whorls; the ribs are bold from the suture to the base and bend sharply to the left just above their midpoint; in the new species they only arise in a subsutural channel and drop perpendicular to the base. The general colour of the latter can be from light brown to orange to mauve/brown, often with some darker pattern on a lighter background just below the suture and again as a narrow band at the top of the aperture, below the widest part of the final whorl. After the submission of this paper, the authors obtained from Jacques Pelorce additional material of Crassispira trencarti spec. nov. and they were able to study its radula which confirms the generic atribution to Crassispira and the specific separation from Drillia tripter. Both radular tooth are very similar, only different in the ratio, which in Crassispira trencarti has LC/DR - 133.
- Crassispira laevisculcata (von Maltzan, 1883) is longer and narrower and lacks spiral cords; colour is lighter.
- Crassispira consociata (E.A. Smith, 1877) is generally larger and decollate, lacking any dark colouration, and juvenile speci¬mens exhibit a multispiral protoconch.
- Crassispira sacerdotalis Rolan and Fernandes, 1992 is narrower, of a uniform colour and with an angular protoconch (ROLAN AND FERNANDES, 1992 fig. 4).
- Crassispira pini Fernandes, Rolan and Otero-Schmitt, 1996 is also endemic to the Dakar area where it is found intertidally under rocks. It is smoother, uniform dark-brown in colour with weaker, more numerous tubercles. FERNANDES ET AL. (1995, fig. 28) illustrate a squat protoconch with strong radial lirations already in the third whorl which are quite different from our species.
- Crassispira fuscobrevis Roldn, Ryall and Horro, 2007 can be of similar size with an intact protoconch but is endemic to south Angola, is stouter in shape and possesses a strong subsutural cord; the latter is generally uniform dark brown, or a little lighter in the subsutural area (i.e. the negative colour aspect of the species just described).

Only known from the immediate area of Dakar, Senegal.