Nominal species of the genus Gyrodactylus von Nordmann 1832 (Monogenea: Gyrodactylidae), with a list of principal host species.

The total diversity of the monogenean genus Gyrodactylus is evaluated. There are 409 potentially valid species names within the genus, recorded from c. 400 host species. Five species have been placed within Fundulotrema and an additional 51 Gyrodactylus species names represent synonyms, nomina nuda or have been reassigned to other non-viviparous monogenean genera. While the majority of Gyrodactylus species (59%) are recorded from single hosts, some have a much broader broad range.