Class Bivalvia Linnaeus, 1758 - bivalves Subclass Autobranchia Grobben, 1894 Superorder Heteroconchia Gray, 1854 Clade Heterodonta Neumayr, 1884 Order Lucinida Gray, 1854 Superfamily Lucinoidea Fleming, 1828 Family †Mactromyidae Cox, 1929 (1887)