Heterodonta is a taxonomic subclass of saltwater clams, marine bivalve molluscs. This subclass includes the edible clams, the cockles and the Venus clams.
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
This subclass contains four extinct orders, five orders of living bivalves, and a group of as yet unassigned Euheterodonta:
Order †Cycloconchidae
Order †Hippuritoida (rudists)
Order †Lyrodesmatidae
Order †Redoniidae
2010 Taxonomy
In 2010, a new proposed classification system for the Bivalvia was published in by Bieler, Carter & Coan, revising the classification of the Bivalvia, including the subclass Heterodonta.
