Class Bivalvia Linnaeus, 1758 - bivalves
Subclass Autobranchia Grobben, 1894
Superorder Heteroconchia Gray, 1854
Clade Palaeoheterodonta Newell, 1965
Order Unionida Gray, 1854
1 ?Superfamily †Archanodontoidea Modell, 1957 [monotypic]
2 Family †Desertellidae Dechaseaux, 1947
3 Family †Trigonodidae Modell, 1942
4 Family †Utschamiellidae Kolesnikov, 1977
5 Superfamily Etherioidea Deshayes, 1832
6 Superfamily Hyrioidea Swainson, 1840 [monotypic]
7 Superfamily †Trigonioidoidea Cox, 1952
8 Superfamily Unionoidea Rafinesque, 1820