Apogastropoda


Apogastropoda was previously used as a major taxonomic grouping of sea snails, marine gastropod molluscs. This infraclass mostly consisted of marine limpets and operculate snails. At least 20,000 species were considered to exist within the two clades that were included, Heterobranchia and Caenogastropoda.

Description

Gastropods that were placed in this taxon have tentacle nerves and two pedal commissures.

Reasons for establishing

Older morphological and molecular studies appeared to show that the Caenogastropoda and Heterobranchia should be considered as sister taxa, comprising the Apogastropoda.
This taxon was used in taxonomy of the Gastropoda.

Reasons for rejection

However this taxonomic grouping is no longer used. It is out-dated because more recent molecular studies have proved that it contains two separate evolutionary lineages, the two clades mentioned above.
Apogastropoda was also rejected according to the nucleotide sequence of mitochondrial genome in 2008.

Synonyms

Apogastropoda comprised taxa as follows according to the taxonomy of the Gastropoda :
Superorder Caenogastropoda Cox, 1960
Superorder Heterobranchia J.E. Gray, 1840