Crassispira pseudoprincipalis is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and their allies.

According to the University of Tokyo, the accepted name is Crassispira pseudoprincipalis,[2] while according to the World Register of Marine Species, the accepted name is Inquisitor pseudoprincipalis.

[3] Both rely on the basionym Pleurotoma (Drillia) pseudoprincipalis Yokoyama, 1920.

According to Makiyama (1927, p. 104), Japanese specimens of this species differ from Crassispira bataviana (Martin, 1895) in having a shorter siphonal canal.

The same appears to be true of the Okinawan and Formosan specimens.