A revision of the species of Bothriocephalus Rudolphi, 1808 (Cestoda: Pseudophyllidea) parasitic in American freshwater fishes

The species of the pseudophyllidean genus Bothriocephalus Rudolphi, 1808 parasitising freshwater fishes in America are revised, based on the examination of type and voucher specimens of seven taxa. There are five valid species: Bothriocephalus claviceps (Goeze, 1782), B. cuspidatus Cooper, 1917, B. formosus Mueller & Van Cleave, 1932, B. acheilognathi Yamaguti, 1934, and B. pearsei Scholz, Vargas-Vázquez & Moravec, 1996. B. texomensis Self, 1954 from Hiodon alosoides in the USA, and B. musculosus Baer, 1937 from a cichlid Cichlasoma biocellatum (= C. octofasciatum) which died in an aquarium in Switzerland, are synonymised with B. cuspidatus. B. schilbeodis Cheng & James, 1960 from Schilbeodes insignis in the USA, B. speciosus (Leidy, 1858) Leidy, 1872 from Boleostoma olmstedi in the USA, and B. cestus Leidy, 1885 from Salvelinus sp. in Canada are considered to be species inquirendae until new material for the evaluation of their taxonomic status is available. B. cordiceps (Leidy, 1872) from Salmo (= Salvelinus) fontinalis in North America is in fact a larva (plerocercoid) of a Diphyllobothrium species. The study showed that there have been many misidentifications, mostly of B. cuspidatus erroneously designated as B. formosus or B. claviceps. The five valid species are redescribed and illustrated, with emphasis on scolex morphology. The distribution of individual taxa and the spectrum of their definitive hosts are briefly reviewed and a key facilitating identification of individual species is also provided.