Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Bivalvia Linnaeus, 1758 - bivalves
     Subclass Heterodonta Neumayr, 1884 see Clade Heterodonta Neumayr, 1884
       Order Chamida see Order Venerida Gray, 1854
         Superfamily Veneroidea Rafinesque, 1815
           Family Veneridae Rafinesque, 1815 - venus clams
             Subfamily Chioninae Frizzell, 1936, nom. illeg.
               Genus Protothaca Dall, 1902
                 1 Subgenus Antinioche Olsson, 1961
                 2 Subgenus Callithaca Dall, 1902
                 3 Subgenus Colonche Olsson, 1961
                 4 Subgenus Leukoma Römer, 1857
                 5 Subgenus Notochione Hertlein & Strong, 1948
                 6 Subgenus Novathaca Habe, 1951
                 7 Subgenus Protocallithaca Nomura, 1937
                 8 Subgenus Tropithaca Olsson, 1961
                 9 Subgenus Tuangia Marwick, 1927