living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Mollusca Linnaeus, 1758 - molluscs
           Class Bivalvia Linnaeus, 1758 - bivalves
             Subclass Paleoheterodonta see Order Unionida Gray, 1854
               Order Unionoida see Order Unionida Gray, 1854
                 Superfamily Unionacea Fleming, 1828 see Superfamily Unionoidea Rafinesque, 1820
                   Family Unionidae Rafinesque, 1820 - pearly mussels
                     Subfamily Popenaiadinae Heard & Guckert, 1970 see Tribe Amblemini Rafinesque, 1820
                       Genus Cyrtonaias Crosse & Fischer, 1894