The clade Multicrustacea constitutes the largest superclass of crustaceans, containing approximately four-fifths of all described crustacean species, including crabs, lobsters, shrimps, woodlice, prawns, krill, barnacles, crayfish, copepods, amphipods and others. The largest branch of multicrustacea is the class Malacostraca (see below).
According to World Register of Marine Species (April 13, 2016) 1 :
Copepod
Sacculina Sacculina carcini (Rhizocephala) parasite of a crab.
Anew Lepas anatifera (Lepadiformes)
Balth Chthamalus stellatus (Sessilia)
Inch-foot Pollicipes polymerus (Scalpelliformes)
Template:Amphionides reynaudii , the unique Amphionidacea known.
Crab Cancer bellianus (Eucarida)
Antarctic Krill Euphausia superba (Euphausiacea)
Atylus swammerdami (Amphipoda)
Diastylis bradyi (Cumacea)
Bathynomus doederleinii (Isopoda)
Gnathophausia zoea (Lophogastrida)
Mictocaris halope (Mictacea)
Gastrosaccus spinifer (Mysida)
Tanaissus lilljeborgi (Tanaidacea)
Tethysbaena ophelicola (Thermosbaenacea)
Koonunga cursor (Anaspidacea)
Shrimp-mantle Odontodactylus scyllarus (Stomatopoda)
Nebalia bipes (Leptostraca)