Species of Gyrodactylus von Nordmann, 1832 (Monogenea: Gyrodactylidae) from freshwater fishes in southern England,with a description of Gyrodactylus rogatensis sp. nov. from the bullhead Cottus gobio L.

Eleven species of Gyrodactylus were found infecting five species of freshwater fishes collected from Rogate (West Sussex, England). These were G. arcuatus and G. gasterostei from Gasterosteus aculeatus, G. pungitii from Pungitius pungitius, G. aphyae, G. laevis, G. limneus, G. macronychus and G. minimus from Phoxinus phoxinus, G. pavlovskyi and G. sedelnikowi from Noemacheilus barbatulus and G. rogatensis n.sp. from Cottus gobio. G. (Limnonephrotus) rogatensis is a member of the G. wageneri species group, and can be distinguished from closely related species (G. aphyae, G. pungitii and G. gasterostei) by its relatively long marginal hooks and by the abruptly tapering toes of its marginal hook sickles. Each parasite was collected from a single host species, and each was narrowly site-specific. With the exception of G. rogatensis, all of the gyrodactylids collected at Rogate also occur in Continental Eurasia, suggesting that they colonized Britain with their hosts via the Doggerland land bridge after the Devensian glaciation. This study demonstrates both the potential of Gyrodactylus for studies of parasite-host coevolution, and the need for critical taxonomic analysis of members of the genus.