Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Bivalvia Linnaeus, 1758 - bivalves
     Subclass Protobranchia Pelseneer, 1889
       Order Nuculida Dall, 1889
         Superfamily Nuculoidea Gray, 1824
           1 Family Nuculidae Gray, 1824 - nut clams
           2 Family Pristiglomidae Sanders & Allen, 1973 see Subfamily Pristiglominae Sanders & Allen, 1973
           3 Family †Praenuculidae McAlester, 1969