Redescription of Rhabdochona papuanensis (Nematoda: Thelazioidea), a parasite of rainbow fishes (Melanotaenia spp.); the first record of the species of Rhabdochona in Australia.

Numerous specimens of the parasitic nematode Rhabdochona papuanensis Moravec, Riha et Kuchta, 2008 (Spirurida: Rhabdochonidae) were collected from the intestines of the Australian endemic freshwater fish (eastern rainbow fish) Melanotaenia splendida (Peters) (Melanotaeniidae, Atheriniformes) in the Behana Creek, North Queesland during November of 2015. Although many species of Rhabdochona Railliet, 1916 are known to be common parasites of fishes in other continents, the present finding of R. papuanensis represents the first record of the species belonging to this genus from the Australian mainland. Light and scanning electron microscopical examinations of these newly collected specimens made it possible to redescribe in detail this nematode species, originally incompletely described from a congeneric host in Papua New Guinea. Fully developed, filamented eggs of R. papuanensis and the conspecific fourth-stage larva are described for the first time. The present finding of R. papuanensis in M. splendida from Australia represents new host and geographical records.