The Lepocreadiidae (Digenea) of fishes of the north-east Atlantic: review of the genera Opechona Looss, 1907 and Prodistomum Linton, 1910

The genera Opechona Looss and Prodistomum Linton are redefined: the latter is re-established, its diagnostic character being the lack of a uroproct. Pharyngora Lebour and Neopechona Stunkard are considered synonyms of Opechona, and Acanthocolpoides Travassos, Freitas & Bührnheim is considered a synonym of Prodistomum. Opechona bacillaris (Molin) and Prodistomum [originally Distomum] polonii (Molin) n. comb. are described from the NE Atlantic Ocean. Separate revisions with keys to Opechona, Prodistomum and ‘Opechona-like’ species incertae sedis are presented. Opechona is considered to contain: O. bacillaris (type-species), O. alaskensis Ward & Fillingham, O. [originally Neopechona] cablei (Stunkard) n. comb., O. chloroscombri Nahhas & Cable, O. occidentalis Montgomery, O. parvasoma Ching sp. inq., O. pharyngodactyla Manter, O. [originally Distomum] pyriforme (Linton) n. comb. and O. sebastodis (Yamaguti). Prodistomum includes: P. gracile Linton (type-species), P. [originally Opechona] girellae (Yamaguti) n. comb., P. [originally Opechona] hynnodi (Yamaguti) n. comb., P. [originally Opechona] menidiae (Manter) n. comb., P. [originally Pharyngora] orientalis (Layman) n. comb., P. polonii and P. [originally Opechona] waltairensis (Madhavi) n. comb. Some species are considered ‘Opechona-like’ species incertae sedis: O. formiae Oshmarin, O. siddiqii Ahmad, 1986 nec 1984, O. mohsini Ahmad, O. magnatestis Gaevskaya & Kovaleva, O. vinodae Ahmad, O. travassosi Ahmad, ‘Lepidapedon’ nelsoni Gupta & Mehrotra and O. siddiqi Ahmad, 1984 nec 1986. The related genera Cephalolepidapedon Yamaguti and Clavogalea Bray and the synonymies of their constituent species are discussed, and further comments are made on related genera and misplaced species. The new combination Clavogalea [originally Stephanostomum] trachinoti (Fischthal & Thomas) is made. The taxonomy, life-history, host-specificity and zoogeography of the genera are briefly discussed.