High diversity of metazoan parasites in carp gudgeons (Eleotridae:Hypseleotrisspp.) from Eastern Australia

Knowledge of the parasite fauna of Australian freshwater fish is fragmentary and incomplete. An understanding of fish hosts and their associated parasites is vital for the successful management of aquatic ecosystems. In this study, we surveyed the parasite fauna of carp gudgeons (Hypseleotrisspp.), a complex of species of Australian freshwater fishes, using morphology and molecular data for the 18S and 28S ribosomal RNA genes. We examined 137 individuals of three different taxa in the carp gudgeon species complex and found 16 parasitic taxa of the Digenea, Cestoda, Nematoda and Arthropoda (five adults and 11 larvae). Eleven parasites are reported for the first time from the carp gudgeons (Pseudodactylogyrussp.,Gyrodactylussp.,Clinostomumsp.,Paradilepis patriciae,P.cf.kempi, two unidentified species ofParadilepis,Dendrouterinasp.,Parvitaeniasp., two lineages of Cyclophyllidea gen. sp.,Procamallanussp., larvae of a spirurine nematode andLernaeasp.), in addition toApatemoncf.hypseleotrisNegm-Eldin & Davies, 2001 and the invasive tapewormSchyzocotyle acheilognathi(Yamaguti, 1934), which were previously reported from these fish hosts. Parasite species richness was double in Lake's and Midgley's carp gudgeons relative to western carp gudgeon. These findings highlight the key role of carp gudgeons as intermediate hosts for multiple parasites with complex life cycles using native birds as definitive hosts and the usefulness of DNA data for the identification of parasite larvae.