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 Tapetinae Gray, 1851
               Genus Irus Schmidt, 1818
                 1 Subgenus Irusella Hertlein & Grant, 1972
                 2 Subgenus Notirus Finlay, 1928
                 3 Subgenus Notopaphia Oliver, 1923
                 4 Subgenus Paphonotia Hertlein & Strong, 1948