Rostroconchia

Taxobox
name = Rostroconchia
fossil_range = Cambrian - Permian
regnum = Animalia
superphylum = Protostomia
phylum = Mollusca
classis = Rostroconchia

The Rostroconchia is a class of extinct mollusks dating from the early Cambrian to the late Permian. They were initially thought to be bivalves, but were later given their own class. They typically have a single, pseudobivalved shell enclosing the mantle and muscular foot. The anterior part of the shell probably pointed downward and had a gap from which the foot could probably emerge. Rostroconchs probably lived a sedentary semi-infaunal lifestyle. There were probably more than 1,000 species of members of this class.