Shell fusiform elongate, with a high spire, solid, the whorls stepped. Protoconch of one and a half smooth whorls, having a depressed nucleus and a peripheral angulation; its diameter is about 700 mu and the colour is light brown. Teleoconch of the holotype with 6-7 whorls, which exhibit prominent, wide and orthocline, or scarcely opisthocline, axial ribs, which (except on the first teleoconch whorls) begin below a subsutural depressed area, finishing on the lower suture; they are wider than their interspaces and on the last whorl fade below the periphery. The last whorl represents 40% of the total height, but in juveniles can reach 50% or more; spiral sculpture formed by numerous and well marked threads which continue up to the base. Aperture oval elongate, with a prominent nodule on the upper part of the columella; siphonal canal short and wide, external lip fine with a deep sinus on the upper part, and strongly rounded anteriorly . Background colouration yellowish-cream or light brown, with isolated dark narrow oblique axial lines irregularly scattered below the suture, and numerous dark spots appearing on the spiral thread on all the shell and down to the base. Dimensions: The holotype is 12.8 mm, the paratypes are smaller.

Crassispira sandrogorii can be differentiated from all other West African species by the very distinct angulate protoconch. Only Crassispira sacerdotalis Rolan and Fernandes, 1992, which is also endemic to this island, has a similar protoconch, but it is smaller, much shorter and mauve/black as against honey brown in our new species. The spire is shorter, the axial nodules are weaker, the shell is monochromatic dark brown and smaller in size (8 - 10 mm)), the spire is much shorter, the axial nodules are weaker, and the shell is monochromatic mauve or black against honey brown in our new species.
Our species has some resemblance to C. trencarti in respect of the randomly scattered dark pigmentations but as mentioned the protoconch is quite distinct, the shoulder is less evident, the colour darker with spiral bands, the spiral sculpture is finer and has more numerous threads.

Only known from the type locality and we believe it is probably endemic to Sao Tome Island or the immediate island group.