Class Bivalvia Linnaeus, 1758 - bivalves
   Subclass Autobranchia Grobben, 1894
     Superorder Heteroconchia Gray, 1854
       Clade Heterodonta Neumayr, 1884
         Order Myida Stoliczka, 1870
           Superfamily Pholadoidea Lamarck, 1809
             Family Pholadidae Lamarck, 1809 - piddocks
               1 Subfamily Pholadinae Lamarck, 1809
               2 Subfamily Jouannetiinae Tryon, 1862
               3 Subfamily Martesiinae Grant & Gale, 1931
               4 Subfamily Xylophaginae Purchon, 1941, nom. illeg. see Family Xylophagaidae Purchon, 1941