Class Bivalvia Linnaeus, 1758 - bivalves Subclass Autobranchia Grobben, 1894 Superorder Heteroconchia Gray, 1854 Clade Heterodonta Neumayr, 1884 Order Pholadomyida Newell, 1965 Septibranchia Pelseneer, 1888 Superfamily Cuspidarioidea Dall, 1886 Family Halonymphidae Scarlato & Starobogatov, 1983