The Cymothoidae are a family of isopods in the suborder Cymothoida found in both marine and freshwater environments. Cymoithoids are ectoparasites, usually of fish, and they include the bizarre "tongue-biter" (Cymothoa exigua), which attaches to a fish's tongue, causing it to atrophy, and replaces the tongue with its own body. Ceratothoa oestroides is one of the most devastating ectoparasites in Mediterranean aquaculture. Around 40 genera and more than 380 species of cymothoid are recognised. Species of the Cymothoidae are generally found in warmer waters and rarely in the cool and cold climates.
Characteristics Cymothoids exhibit various adaptations to their parasitic lifestyles. As juveniles, they are not specific in their requirements, and attach themselves temporarily to the skin of any fish. They produce anticoagulants and suck the fish's blood. They detach from their first host and later find another host. When they have found the correct species of fish for their adult development, they attach more permanently. As adults, most species require a particular host species, and are also site-specific. Locations for attachment chosen by different species of parasite include the skin, fins, gills, and mouth, while some species bore into muscle.
Biology Cymothoids are protandrous hermaphrodites; each juvenile develops first into a male, but if no females are nearby, the male later becomes a female and attaches permanently to the host. This female is able to secrete pheromones that prevent male cymothoids in the vicinity from becoming female. These parasites can cause serious damage to their hosts, ranging from slow growth rate, through tissue damage and anaemia, to death. Many host fish have mutualistic arrangements with certain shrimps such as Ancylomenes pedersoni, whereby the fish visits a "cleaning station" and the shrimps remove and feed on the cymothoid parasites.
Classification According to the World Register of Marine Species, the family contains these genera:
Aegathoa Dana, 1853 Agarna Schioedte & Meinert, 1884 Amblycephalon Pillai, 1954 Anilocra Leach, 1818 Anphira Thatcher, 1993 Artystone Schioedte, 1866 Asotana Schioedte & Meinert, 1881 Braga Schioedte & Meinert, 1881 Catoessa Schioedte & Meinert, 1884 Ceratothoa Dana, 1852 Cinusa Schioedte & Meinert, 1884 Creniola Bruce, 1987 Cterissa Schioedte & Meinert, 1884 Cymothoa Fabricius, 1787 Elthusa Schioedte & Meinert, 1884 Emetha Schioedte & Meinert, 1883 Glossobius Schioedte & Meinert, 1883 Ichthyoxenus Herklots, 1870 Idusa Schioedte & Meinert, 1884 Isonebula Taberner, 1977 Joryma Bowman & Tareen, 1983 Kuna Williams & Williams, 1986 Lathraena Schioedte & Meinert, 1881 Livoneca Leach, 1818 Lobothorax Bleeker, 1857 Mothocya Costa in Hope, 1851 Nerocila Leach, 1818 Norileca Bruce, 1990 Olencira Leach, 1818 Ourozeuktes H. Milne-Edwards, 1840 Paracymothoa Lemos de Castro, 1955 Philostomella Szidat & Schubart, 1960 Pleopodias Richardson, 1910 Plotor Schioedte & Meinert, 1881 Pseudoirona Pillai, 1964 Renocila Miers, 1880 Rhiothra Schioedte & Meinert, 1884 Riggia Szidat, 1948 Ryukyua Williams & Bunkley-Williams, 1994 Smenispa Özdikmen, 2009 Telotha Schioedte & Meinert, 1884 Tetragonocephalon Avdeev, 1978
References
Further reading
External links