The genus Hemionchos Campbell & Beveridge, 2006 (Cestoda: Trypanorhyncha) in Australian manta rays (Batoidea: Mobulidae)

New species of Hemionchos (Cestoda: Trypanorhyncha) are reported from the spiral valve of the manta ray Mobula alfredi (Krefft) from the Great Barrier Reef, Queensland, representing the first record of this genus from Australian waters. Four undescribed species were identified from the spiral valve contents of a single ray. A relatively complete description is presented for H. australis sp. nov. The remaining three new species are described but as the descriptions are incomplete, they have not been named. This study suggests a much higher degree of diversity within the genus Hemionchos than hitherto suspected and that the examination of additional species of manta and devil rays will yield more new species. The genus is redefined based on the addition of new species and a key to the species is provided.