Plesiothyreus Cossmann 1888 (snail)
Gastropoda - Neritoidea - Phenacolepadidae
Parent taxon: Phenacolepadidae according to P. Lozouet et al. 2001
Sister taxa: Cinnalepeta, Phenacolepas, Shinkailepas
Subtaxa: Plesiothyreus ancyliformis, Plesiothyreus parmophoroides
Type: Capulus parmophoroides
Ecology: epifaunal omnivore