Class Bivalvia Linnaeus, 1758 - bivalves Subclass Autobranchia Grobben, 1894 Superorder Heteroconchia Gray, 1854 Clade Palaeoheterodonta Newell, 1965 Order Trigoniida Dall, 1889 Superfamily †Myophorelloidea Kobayashi, 1954 Family †Buchotrigoniidae Leanza, 1993 Subfamily †Syrotrigoniinae Pérez & Reyes, 1997