The Gnathiidae are a family of isopodcrustaceans. 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.[1] The juvenile form is known as a 'praniza', and it is a temporary parasite of marine fish.[1][2] 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.
Taxonomy in the family relies on male characters, such that females and juveniles cannot be reliably identified.[1] The family contains 182 species,[3] divided among the following genera:[4]
^ abHesse, Eugène (1864). Mémoire sur les pranizes et les ancées et sur les moyens curieux à l'aide desquels certains crustacés parasites assurent la conservation de leur espèce. Extrait du Tome XMII des Mémoires Présentés par Divers Savants à l'Institut Impérial de France. Paris, J. B. Baillière et Fils, Libraire de l’Académie Impériale de Médecine. BHL PDF in BHL
^WoRMS (2010). M. Schotte; C. B. Boyko; N. L. Bruce; G. C. B. Poore; S. Taiti; G. D. F. Wilson (eds.). "Gnathiidae". World Marine, Freshwater and Terrestrial Isopod Crustaceans database. World Register of Marine Species. Retrieved August 28, 2010.