Two Species of Acanthocephala from Australian Fishes with Description of \u3ci\u3eArhythmacanthus paraplagusiarum\u3c/i\u3e sp. n.

Two South Australian garfish, Hemirhamphus melanochir, collected near Adelaide, South Australia, harbored 14 and 15 specimens of Micracanthorhynchina hemirhamphi. Arhythmacanthus paraplagusiarum sp. n. is described from 10 specimens collected from Paraplagusia guttata taken from Moreton Bay, Brisbane, Queensland. A. paraplagusiarum differs from other species of the genus in length of the enlarged subapical proboscis hooks. These hooks are 120 to 132 μm long in females and 113 to 120 μm long in males of A. paraplagusiarum, 188 to 210 μm long in A. fusiformis, and 60 μm long in A. septacanthus. Males of A. paraplagusiarum have proboscides 182 to 206 μm long compared to proboscides 340 to 430 μm long in A. fusiformis