The Gnathiidae are a family of isopod crustaceans. They occur in a wide range of depths, from the littoral zone to the deep sea. The adults are associated with sponges and may not feed. The juvenile form is known as a 'praniza', and it is a temporary parasite of marine fish. These forms are not larvae; Gnathiidae instead become parasitic during the manca stage. Mancae of the Gnathiidae closely resemble the adult form, however they lack the final pair of pereiopods.
The Valvifera are marine isopod crustaceans. Valviferans are distinguished, however, by the flat, valve-like uropods which hinge laterally and fold inward beneath the rear part of their bodies, covering the pleopods. Some species are omnivorous, and serve as effective scavengers in the economy of the sea.
Sphaeromatidae is a family of isopods, often encountered on rocky shores and in shelf waters in temperate zones. The family includes almost 100 genera and 619 known marine species. Within these genera, there are groups that share distinctive morphologies; further research may reclassify these genus-groups as separate families.
Iais is a genus of isopod crustaceans. Iais species are found in association with larger isopods of the family Sphaeromatidae, usually on the ventral surface of the larger animal, between the pereiopods and on the pleopods. They are native to Australasia and South America, although Iais californica and its host Sphaeroma quoyanum have invaded California, and I. californica was first described from Sausalito, California. Nine species are recognised:
Eurydice is a genus of isopod crustaceans named after the mythical Eurydice, wife of the musician Orpheus. It includes the following species:
The Cirolanidae are a family of isopod crustaceans, including these genera:
Paracerceis is a genus of isopod crustacean in the family Sphaeromatidae. It contains the following species:
The Leptanthuridae are a family of isopod crustaceans, containing the following genera:
Cymothoida is the name of a suborder of isopod crustaceans with a mostly carnivorous or parasitic lifestyle. It contains more than 2,700 described species in four superfamilies. Members of the suborder are characterised by their specialised mouthparts which include a mandible with a tooth-like process which is adapted for cutting or slicing.
Gnathia is a genus of isopod crustaceans, containing the following species:
The Bopyridae are a family of isopod crustaceans in the suborder Cymothoida. There are 1223 individual species contained in this family. Members of the family are ectoparasites of crabs and shrimp. They live in the gill cavities or under the carapace where they cause a noticeable swelling. Fossil crustaceans have occasionally been observed to have a similar characteristic bulge.
Cancricepon is a genus of isopod crustaceans in the family Bopyridae. It has been synonymised with Merocepon Richardson, 1910.
Chiridotea is a genus of isopod crustaceans in the family Chaetiliidae, containing the following species:
The Chaetiliidae are a family of isopod crustaceans in the suborder Valvifera, comprising these genera:
Saduria is a genus of benthic isopod crustaceans in the family Chaetiliidae, containing the following species:
The Arcturidae are a family of marine isopod crustaceans in the suborder Valvifera. Members of the family resemble woodlice and are found globally in cooler areas in shallow seas.
Cirolana is a genus of isopod crustaceans.
Aega is a genus of isopods in the family Aegidae, containing the following species:
Idotea neglecta is a marine isopod in the family Idoteidae. It can be found on algae in the littoral and sublittoral zone of north-west European coasts.
Euidotea is a genus of marine isopods belonging to the family Idoteidae. The species of this genus are found in Australia and New Zealand.
