Heteroconchia is a taxonomic infraclass of saltwater clams, marine bivalve molluscs, belonging to the subclass Autobranchia[1]
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.[2]
The following tree is their info which has been updated with the latest information from the World Register of Marine Species:[1]