Class Bivalvia Linnaeus, 1758 - bivalves Subclass Autobranchia Grobben, 1894 Superorder Pteriomorphia Beurlen, 1944 Order Ostreida Férussac, 1822 [monotypic] Superfamily Ostreoidea Rafinesque, 1815 Family Gryphaeidae Vialov, 1936 Subfamily Pycnodonteinae Stenzel, 1959 Tribe Hyotissini Scarlato & Starobogatov, 1979