Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Bivalvia Linnaeus, 1758 - bivalves
     Subclass Heterodonta Neumayr, 1884 see Clade Heterodonta Neumayr, 1884
       Order Myida Stoliczka, 1870
         Suborder Myina Stoliczka, 1870 see Superfamily Myoidea Lamarck, 1809
           Superfamily Hiatelloidea Gray, 1824 [monotypic]
             Family Hiatellidae Gray, 1824 - geoducks
               Genus Cyrtodaria Reuss, 1801