Heteroconchia

Heteroconchia is a taxonomic infraclass of diverse bivalve molluscs, belonging to the subclass Autobranchia.

This infraclass includes the cockles, Venus clams, the freshwater mussels, brooch clams, as well as Heterodonta and Archiheterodonta.

Description
These bivalves are distinguished by having the two halves of the shell equally sized (i.e, they are equivalved) and having a few cardinal teeth separated from a number of long lateral teeth. Their shells lack a nacreous layer, and the gills are lamellibranch in form. Most species have a siphon.

Orders and families
The following tree is their info which has been updated with the latest information from the World Register of Marine Species:

Infraclass: Heteroconchia


 * Unclassified family: †Lipanellidae
 * Subterclass: Archiheterodonta
 * Order: †Actinodontida
 * Superfamily: †Amnigenioidea
 * Family: †Amnigeniidae
 * Family: †Montanariidae
 * Family: †Zadimerodiidae
 * Superfamily: †Anodontopsoidea
 * Family: †Actinodontidae
 * Family: †Anodontopsidae
 * Family: †Baidiostracidae
 * Family: †Cycloconchidae
 * Family: †Intihuarellidae
 * Family: †Redoniidae
 * Superfamily: †Nyassoidea
 * Family: †Nyassidae
 * Superfamily: †Oriocrassatelloidea
 * Family: †Crassatellopsidae
 * Family: †Oriocrassatellidae
 * Superfamily: †Palaeomuteloidea
 * Family: †Palaeomutelidae
 * Order: Carditida
 * Unclassified family: †Archaeocardiidae
 * Unclassified family: †Eodonidae
 * Superfamily: Carditoidea
 * Family: †Cardiniidae
 * Family: Carditidae
 * Family: Condylocardiidae
 * Superfamily: Crassatelloidea
 * Family: †Aenigmoconchidae
 * Family: Astartidae
 * Family: Crassatellidae
 * Family: †Myophoricardiidae
 * Subterclass: Euheterodonta 
 * Unassigned Euheterodonta
 * Superfamily: †Babinkoidea
 * Superfamily: †Orthonotoidea
 * Superorder: Anomalodesmata
 * Superfamily: Clavagelloidea
 * Family: Clavagellidae
 * Family: Penicillidae
 * Superfamily: Cuspidarioidea
 * Family: Cuspidariidae
 * Family: Halonymphidae
 * Family: Protocuspidariidae
 * Family: Spheniopsidae
 * Superfamily: Myochamoidea
 * Family: Cleidothaeridae
 * Family: Myochamidae
 * Superfamily: Pandoroidea
 * Family: Lyonsiidae
 * Family: Pandoridae
 * Superfamily: Pholadomyoidea
 * Family: †Arenigomyidae
 * Family: †Margaritariidae
 * Family: Parilimyidae
 * Family: Pholadomyidae
 * Family: †Ucumariidae
 * Superfamily: Poromyoidea
 * Family: Cetoconchidae
 * Family: Poromyidae
 * Superfamily: Thracioidea
 * Family: †Burmesiidae
 * Family: Clistoconchidae
 * Family: Laternulidae
 * Family: Periplomatidae
 * Family: Thraciidae
 * Superfamily: Verticordioidea
 * Family: Euciroidae
 * Family: Lyonsiellidae
 * Family: Verticordiidae
 * Superorder: Imparidentia
 * Unassigned Imparidentia
 * Unassigned Family: †Palaeocarditidae
 * Superfamily: Cyamioidea
 * Family: Cyamiidae
 * Family: Galatheavalvidae
 * Family: Sportellidae
 * Superfamily: Gaimardioidea
 * Family: Gaimardiidae
 * Superfamily: †Grammysioidea
 * Family: †Grammysiidae
 * Family: †Sanguinolitidae
 * Superfamily: †Kalenteroidea
 * Family: †Kalenteridae
 * Order: Adapedonta
 * Superfamily: †Edmondioidea
 * Family: †Edmondiidae
 * Family: †Pachydomidae
 * Superfamily: Hiatelloidea
 * Family: Hiatellidae
 * Superfamily: Solenoidea
 * Family: Pharidae
 * Family: Solenidae
 * Order: Cardiida
 * Superfamily: Cardioidea
 * Family: Cardiidae
 * Family: †Pterocardiidae
 * Superfamily: Tellinoidea
 * Family: Donacidae
 * Family: †Icanotiidae
 * Family: Psammobiidae
 * Family: †Quenstedtiidae
 * Family: Semelidae
 * Family: Solecurtidae
 * Family: †Sowerbyidae
 * Family: †Tancrediidae
 * Family: Tellinidae
 * Family: †Unicardiopsidae
 * Order: Galeommatida
 * Superfamily: Galeommatoidea
 * Family: Basterotiidae
 * Family: Galeommatidae
 * Family: Lasaeidae
 * Order: Gastrochaenida
 * Superfamily: Gastrochaenoidea
 * Family: Gastrochaenidae
 * Order: †Hippuritida (rudists)
 * Suborder: †Hippuritidina
 * Superfamily: †Caprinoidea
 * Family: †Antillocaprinidae
 * Family: †Caprinidae
 * Family: †Caprinuloideidae
 * Family: †Ichthyosarcolitidae
 * Superfamily: †Radiolitoidea
 * Family: †Caprinulidae
 * Family: †Caprotinidae
 * Family: †Diceratidae
 * Family: †Hippuritidae
 * Family: †Monopleuridae
 * Family: †Plagioptychidae
 * Family: †Polyconitidae
 * Family: †Radiolitidae
 * Family: †Trechmannellidae
 * Suborder: †Requieniidina
 * Superfamily: †Requienioidea
 * Family: †Epidiceratidae
 * Family: †Requieniidae
 * Order: Lucinida
 * Superfamily: Lucinoidea
 * Family: Lucinidae
 * Family: †Mactromyidae
 * Family: †Paracyclidae
 * Superfamily: Thyasiroidea
 * Family: Thyasiridae
 * Order: †Megalodontida
 * Superfamily: †Mecynodontoidea
 * Family: †Beichuaniidae
 * Family: †Congeriomorphidae
 * Family: †Mecynodontidae
 * Family: †Plethocardiidae
 * Family: †Prosocoelidae
 * Superfamily: †Megalodontoidea
 * Family: †Ceratomyopsidae
 * Family: †Dicerocardiidae
 * Family: †Megalodontidae
 * Family: †Pachyrismatidae
 * Family: †Wallowaconchidae
 * Order: †Modiomorphida
 * Superfamily: †Modiomorphoidea
 * Family: †Cypricardiniidae
 * Family: †Hippopodiumidae
 * Family: †Modiomorphidae
 * Family: †Palaeopharidae
 * Family: †Tusayanidae
 * Order: Myida
 * Superfamily: Dreissenoidea
 * Family: Dreissenidae
 * Superfamily: Myoidea
 * Family: Corbulidae
 * Family: Myidae
 * Family: †Pleurodesmatidae
 * Family: †Raetomyidae
 * Superfamily: Pholadoidea
 * Family: Pholadidae
 * Family: Teredinidae (shipworms)
 * Family: Xylophagaidae
 * Superfamily: †Pleuromyoidea
 * Family: †Ceratomyidae
 * Family: †Pleuromyidae
 * Family: †Vacunellidae
 * Order: Sphaeriida
 * Superfamily: Sphaerioidea
 * Family: †Neomiodontidae
 * Family: Sphaeriidae
 * Order: Venerida
 * Superfamily: †Anthracosioidea
 * Family: †Anthracosiidae
 * Family: †Ferganoconchida
 * Family: †Shaanxiconchidae
 * Superfamily: Arcticoidea
 * Family: Arcticidae
 * Family: †Pollicidae
 * Family: Trapezidae
 * Family: †Veniellidae
 * Superfamily: Chamoidea
 * Family: Chamidae
 * Superfamily: Cyrenoidea
 * Family: Cyrenidae
 * Family: Cyrenoididae
 * Family: Glauconomidae
 * Superfamily: Glossoidea
 * Family: Glossidae
 * Family: Kelliellidae
 * Family: †Lutetiidae
 * Family: Vesicomyidae
 * Superfamily: Hemidonacoidea
 * Family: Hemidonacidae
 * Superfamily: Mactroidea
 * Family: Anatinellidae
 * Family: Cardiliidae
 * Family: Mactridae
 * Family: Mesodesmatidae
 * Superfamily: †Palaeanodontoidea
 * Family: †Palaeanodontidae
 * Superfamily: †Prilukielloidea
 * Family: †Prilukiellidae
 * Family: †Senderzoniellidae
 * Superfamily: Ungulinoidea
 * Family: Ungulinidae
 * Superfamily: Veneroidea
 * Family: †Isocyprinidae
 * Family: Neoleptonidae
 * Family: Veneridae
 * Subterclass: Paleoheterodonta
 * Unassigned Family: Lyrodesmatidae
 * Unassigned Family: Pseudarcidae
 * Unassigned Family: Thoraliidae
 * Order: Unionida
 * Unassigned Genus †Araripenaia
 * Unassigned Family †Pachycardiidae
 * Superfamily Etherioidea
 * Superfamily †Silesunionoidea
 * Superfamily †Tamesnelloidea
 * Superfamily Unionoidea
 * Order: Trigoniida
 * Superfamily †Megatrigonioidea
 * Superfamily Myophorelloidea
 * Superfamily Pseudocardinioidea
 * Superfamily Trigonioidea
 * Superfamily Trigonioidoidea
 * Superfamily Trigonodoidea
 * Subterclass: Heterodonta