Empruthotrema tasmaniensis sp. nov. is described from the nasal fossae of the southern eagle ray, Myliobatis australis Macleay (Myliobatidae), from the east coast of Tasmania. Empruthotrema tasmaniensis is distinguished from others in the genus by the presence of an accessory piece associated with the male copulatory organ; no other species of Empruthotrema Johnston and Tiegs, 1922 has an accessory piece. Merizocotyle urolophi sp. nov. is described from the nasal fossae of the sparsely spotted stingaree, Urolophus paucimaculatus Dixon (Urolophidae), and is distinguished from other members of the genus by 12 marginal loculi on the haptor; this is the only species of Merizocotyle Cerfontaine, 1894 that has this configuration. Squalotrema llewellyni Kearn and Green, 1983, described previously from Squalus acanthias Linnaeus (Squalidae) from the English Channel, is recorded from the same host species caught off the east coast of Tasmania. We found Triloculotrema japanica Kearn, 1993, which was described originally in the nasal fossae of the Japanese topeshark, Hemitriakis japanica (Müller and Henle) (Triakidae), off Minabe, Japan, in the nasal fossae of Mustelus antarcticus (Günther) (Triakidae) caught off the east coast of Tasmania. Merizocotyle australensis (Beverley-Burton and Williams, 1989) Chisholm, Wheeler and Beverley-Burton, 1995, found in the nasal fossae of Himantura uarnak collected from Darwin, represents a new host and locality record. Empruthotrema and Merizocotyle are revised fully and additional information is provided for Squalotrema Kearn and Green, 1983 and Triloculotrema Kearn, 1993. A key is given to the Merizocotylinae Johnston and Tiegs, 1922 and illustrations are provided of all important taxonomic characters. We postulate how the different types of haptors found in Empruthotrema and Merizocotyle may have been derived and discuss the taxonomy of Merizocotyle which is still in a poor state.