†family Grammysiidae Miller 1877 (clam)
Parent taxon: Grammysioidea according to J. G. Carter et al. 2011
Sister taxon: Sanguinolitidae
Subtaxa: Asketomorpha, Cardiomorpha, Cercomyopsis, Cimitaria, Cuneamya, Cuneamyinae, Ectogrammysia, Fuchsella, Glossites, Grammysia, Grammysiinae, Grammysioidea, Prothyris, Sedgwickia, Solenomorpha
Ecology: facultatively mobile infaunal suspension feeder