Phylum Mollusca Linnaeus, 1758 - molluscs
Class Gastropoda Cuvier, 1795 - snails and slugs
Subclass Divasibranchia Minichev & Starobogatov, 1975
Order Basommatophora Keferstein, 1865
see Suborder Basommatophora Keferstein, in Bronn, 1864
Superfamily Planorbioidea Vaught, 1989, orth. inval.
see Superfamily Planorboidea Rafinesque, 1815
Family Ancylidae Rafinesque, 1815 - freshwater limpets
see Tribe Ancylini Rafinesque, 1815
Subfamily Ferrissiinae Walker, 1917
see Tribe Miratestini Sarasin & Sarasin, 1897
Genus Laevapex Walker, 1903
1 Subgenus Pettancylus Iredale, 1943