Gordioidea
Gordioidea is an order of parasitic horsehair worms. Its taxonomy remains uncertain, but appears to be contained in the monotypic class Gordioida and contains about 320 known species.
Biology
Gordioidean adults are free-living in freshwater or semi-terrestrial habitats and larvae parasitise insects, primarily Orthopterans. Unlike Nectonematoideans, which are marine, gordioideans lack lateral rows of setae and have a single, ventral epidermal cord and their blastocoel is filled with mesenchyme in young worms but become open when older.Families and genera
The Integrated Taxonomic Information System lists the following genera in two families:[Chordodidae]
Auth. May, 1919; selected genera:;Subfamily Chordodinae Heinze, 1935Chordodes Creplin, 1847Dacochordodes Capuse, 1965Euchordodes Heinze, 1937Neochordodes Carvalho, 1942Pantachordodes Heinze, 1954Spinochordodes Kirjanova, 1950
;Subfamily ParagordiinaeParagordius Camerano, 1897
;incertae sedisGordionus Müller, 1927Parachordodes Camerano, 1897Paragordionus Heinze, 1935Semigordionus Heinze, 1952