Doridoidea, commonly known as dorid nudibranchs (and previously known as the taxon Cryptobranchia), are a taxonomic superfamily of medium to large, shell-less sea slugs, marine gastropod mollusks in the clade Doridacea, included in the clade Nudibranchia.
The word "Doridoidea" comes from the generic name Doris, which was in turn copied from the name of the sea nymph, Doris, in Greek mythology.
According to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), families within the superfamily Doridoidea include:
The family Cadlinidae <small>Bergh, 1891</small> was considered a synonym of the Chromodorididae. Research by R.F. Johnson in 2011 has shown that Cadlina does not belong to the family Chromodorididae. She has therefore brought back the name Cadlinidae from synonymy with Chromodorididae. The chromodorid nudibranchs without Cadlina are now monophyletic and turn out to be a possible sister to the Actinocyclidae
The next families are considered synonyms. But these names can still be found in many publications and on the internet.
Cryptobranch dorid nudibranchs (previously known as the taxon Cryptobranchia), are nudibranch sea slugs within the clade Doridacea. These slugs are called "cryptobranch," meaning "hidden gill", because they are able to retract their gills into a gill pocket, in contrast to nudibranchs in the traditional group phanerobranchs (or Phanerobranchia), which taxon is probably paraphyletic (in other words, composed of more than one evolutionary lineage).
A. Valdés distinguishes two major clades within the Cryptobranchia: the dorids that have no radula (the Porostomata); and those with a radula (the Labiostomata). The Labiostomata include the monophyletic families: Actinocyclidae, Chromodorididae, Dorididae and Discodorididae.
The cryptobranchs include the following genera that are regarded as valid: