A new species of <i>Rhipidocotyle</i> Diesing, 1858 (Trematoda: Bucephalidae) infecting leerfish, <i>Lichia amia</i> (L.) (Teleostei: Carangidae), and the first complete life-cycle for a marine trematode from Southern Africa

We present the first elucidated marine trematode life-cycle for southern Africa, involving intermediate and definitive hosts from the southwestern Indian Ocean, through southern South Africa and to the southeastern Atlantic Ocean in Namibia. Adults of <i>Rhipidocotyle meridionalis</i> n. sp. were found infecting leerfish, <i>Lichia amia</i> (L.) (Carangiformes: Carangidae), in the Tsitsikamma section of Garden Route National Park, South Africa. Bucephalid sporocysts and cercariae isolated from a brown mussel, <i>Perna perna</i> (L.) (Bivalvia: Mytilidae), were subsequently recovered from the same area and are a perfect genetic match with adults of <i>R. meridionalis</i> n. sp. based on the partial 28S rDNA region. Metacercariae encysted in multiple organs of the following fishes were found to genetically match this taxon: <i>Chelon richardsonii</i> (Smith) (Mugiliformes: Mugilidae), <i>Dichistius capensis</i> (Cuvier) (Centrarchiformes: Dichistiidae) and <i>Diplodus capensis</i> (Smith) (Eupercaria <i>i. s.</i>: Sparidae) from the coast between Swakopmund and Walvis Bay, Namibia; <i>Chelon dumerili</i> (Steindachner) (Mugiliformes: Mugilidae), <i>Chrysoblephus laticeps</i> (Valenciennes), <i>Dip. capensis, Sarpa salpa</i> (L.) and <i>Sparodon durbanensis</i> (Castelnau) (Eupercaria <i>i. s.</i>: Sparidae) from Tsitsikamma; <i>Amblyrhynchote honckenii</i> (Bloch) (Tetraodontiformes: Tetraodontidae) and <i>Rhabdosargus holubi</i> (Steindachner) (Eupercaria <i>i. s.</i>: Sparidae) from Witsand; <i>A. honckenii</i> from Chintsa, De Hoop Nature Reserve and Uvongo; and <i>Dip. capensis</i> from Mossel Bay. The southern coast of South Africa, where the type-locality of <i>R. meridionalis</i> n. sp. is located, is influenced by both cold Atlantic and warm Indian Ocean currents and is thus subjected to complex hydrological patterns. This life-cycle, linking hosts present in both oceans, informs both the picture of host- and trematode connectivity in southern Africa.