# 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