†family Mactromyidae Cox 1929 (clam)
Parent taxon: Lucinoidea according to J. G. Carter et al. 2011
Sister taxa: Lucinidae, Paracyclidae
Subtaxa: Bathycorbis, Clisocolus, Cordiula, Linetia, Mactromya, Mactromyopsis, Montanaria, Palaeolucina, Paracyclas, Plesiocyprinella, Sexta, Thetironia, Thetis, Unicardium
Ecology: facultatively mobile infaunal chemosymbiotic