Dactylogyrids (Monogenoidea) infecting the gill lamellae of some beloniform fishes from Moreton Bay, Queensland, Australia, with a redescription of Hareocephalus thaisae Young, 1969 and descriptions of six new species of Hemirhamphiculus Bychowsky & Nagibina, 1969.

Three species of beloniform fishes were found infected with species of Monogenoidea Bychowsky, 1937 during a survey of the diversity of parasites infecting the fishes of Moreton Bay, Queensland, Australia. The diagnoses of Hareocephalus Young, 1969 and Hemirhamphiculus Bychowsky & Nagibina, 1969 (both Polyonchoinea Bychowsky, 1937: Dactylogyridae Bychowsky, 1933) were emended. Hareocephalus thiasae Young, 1969, type-species of the genus, was recorded and redescribed from the gill lamellae of the stout longtom Tylosurus gavialoides (Castelnau) (Belonidae), and six new species of Hemirhamphiculus were described from the gill lamellae of three host species: Hemirhamphiculus exserocephalus n. sp. from T. gavialoides; Hemirhamphiculus choanophallus n. sp. and Hemirhamphiculus flagrum n. sp. from the river garfish Hyporhamphus regularis (Günther) (Hemiramphidae); and Hemirhamphiculus perexiguus n. sp., Hemirhamphiculus krabsi n. sp., and Hemirhamphiculus imcomptus n. sp. from the southeastern snub-nose garfish Arrhamphus sclerolepis krefftii (Steindachner) (Hemiramphidae). An unidentified species of the Suborder Microcotylinea Lebedev, 1972 (Heteronchoinea Boeger & Kritsky, 2001) was found infecting single specimens of each of H. regularis and A. sclerolepis krefftii. Parahemirhamphiculus Bychowsky & Nagibina, 1969 is placed in junior subjective synonymy with Hemirhamphiculus, and its three species, Parahemirhamphiculus pinguis Bychowsky & Nagibina, 1969, Parahemirhamphiculus brevilamellatus Zhang, 2001, and Parahemirhamphiculus longilamellatus An & Zhang, 1988 are transferred to Hemirhamphiculus.