Crassispira rudis, common name the rustic pleurotoma, is a species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae.

(Original description) The thick, turreted shell is very dark brown, almost black.

The whorls are contracted in the middle, tuberculated above and below, each of the lower tubercles having a white spot above it.

The body whorl is rather out of the centre.

The outer lip is thin, sinuous, armed above the sinus with a strong callosity [2] This marine species occurs between the Sea of Cortez, Western Mexico and Ecuador