Redescription of Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786) (Cestoda: Pseudophyllidea), parasites of fish in the Holarctic Region

• Main Authors: Kuchta, Roman, Hanzelova, Vladimira, Shinn, Andrew, Poddubnaya, Larisa, Scholz, Tomas
• Other Authors: Czech Academy of Sciences, Slovak Academy of Sciences, Institute of Aquaculture, Russian Academy of Sciences, Russia, orcid:0000-0002-5434-2685
• Format: Article in Journal/Newspaper
• Language: English
• Published: Czechoslovak Academy of Institute of Parasitology 2005
• Subjects: Eubothrium fragile; Eubothrium rugosum; redescription; fish cestodes; Lota lota; Alosa fallax; morphology; Burbot; lota
• Online Access: http://hdl.handle.net/1893/10207; http://folia.paru.cas.cz/detail.php?id=20763; http://dspace.stir.ac.uk/bitstream/1893/10207/1/Kuchta%20et%20al%20Folia%20Parasitologica%202005.pdf

Two fish cestodes, the little-known Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786), the type species of the genus Eubothrium Nybelin, 1922, are redescribed on the basis of new material from twaite shad, Alosa fallax (Lacépède, 1803), from England and burbot, Lota lota (Linnaeus, 1758), from Russia, respectively. The tapeworms are compared with two other species of the genus, E. crassum (Bloch, 1779) and E. salvelini (Schrank, 1790), common parasites of salmonid fish in the Holarctic. The most notable differential characters are the size and the shape of the scolex (smaller and oval in E. fragile), the shape of the apical disc (four or more indentations in E. crassum), the number and size of the testes (the largest and least numerous in E. rugosum), and the position and size of the vitelline follicles (almost entirely cortical in distribution in E. fragile and E. crassum versus largely medullary in E. rugosum and E. salvelini). A comparison of species has also shown the morphological similarity of the freshwater species (E. rugosum and E. salvelini) on one hand and those of marine origin, E. fragile and E. crassum, on the other, with the latter species occurring also in fresh waters. A key to the identification of the species studied is also provided.