A new species of Paradiplozoon (Polyopisthocotyla: Diplozoidae) from two near threatened endemic cyprinid hosts in South Africa’s Cape Fold freshwater ecoregion

Paradiplozoon jordaanae n. sp. is described from the gills of two near threatened endemic freshwater fishes, Cheilobarbus serra (Peters) and Sedercypris calidus (Barnard), from the Matjies and Rondegat rivers, respectively, in the Cape Fold Ecoregion, South Africa. Paradiplozoon jordaanae n. sp. can be morphologically distinguished from the three known South African species of Paradiplozoon ( Paradiplozoon ichthyoxanthon , Paradiplozoon krugerense and Paradiplozoon vaalense ) in the less pronounced cucullate terminal protrusion on the haptor, surface plicae, and the absence of an egg filament. Further, a well-developed bifurcate projection on the anterior end of the median plate of the clamp, distinguish the new species from other South African species. From inferences using the ITS2 and 28S rDNA gene regions, Paradiplozoon jordaanae n. sp. clustered sister to P. ichthyoxanthon with P. vaalense as the closest related species to the couple. Along with the description of Paradiplozoon jordaanae n. sp., the present study i) introduces endemic cyprinids of the Smiliogastrinae as suitable hosts for species of Paradiplozoon ; ii) reports on the first fish diplozoid from the Cape Fold Ecoregion; iii) provides an integrated description to characterise Paradiplozoon jordaanae n. sp. molecularly and morphologically, and iv) emphasises the importance of the study of threatened endemic ichthyofaunal diversity that has largely gone unnoticed and unexplored for almost four decades in South Africa. • New Paradiplazoon species from threatened South African cyprinids described. • Integrated approach: light microscopy, SEM, molecular methods applied. • Parasite fauna of threatened hosts reveals hidden biodiversity.