Ascaridoid nematodes referable to Brevimulticaecum heterotis (Petter, Vassiliadès et Marchand, 1979) Khalil, 1984 were recorded from the intestine of the African bonytongue, Heterotis niloticus (Cuvier) (Arapaimidae, Osteoglossiformes), from the Mare Simenti in the Niokolo Koba National Park, East Senegal and from Kosti, Sudan. Their examination using light microscopy and for the first time both environmental scanning electron microscopy and scanning electron microscopy revealed some previously unreported morphological features and made possible a detailed redescription of this species. The most important finding is the presence of dentigerous ridges on the inner edges of the lips, which confirms the attribution of this species to Multicaecum Baylis, 1923, where it was originally placed, and not to Brevimulticaecum Mozgovoy in Skryabin, Shikhobalova et Mozgovoy, 1951 where it had subsequently been transferred. A key to Brevimulticaecum and Multicaecum species is provided. Multicaecum heterotis is the first species of the genus to be sequenced. Partial sequences of the small ribosomal subunit (18S) and internal transcribed spacer 2 region (ITS2) of nuclear ribosomal DNA (rDNA) have been analysed and compared with other nematode species.
This study revises the originally monotypic genus Afrogyrodactylus Paperna, 1968 (Monogenea), the species of which infect alestid fish (Characiformes) in Africa, and includes new records of these parasites from three geographically distant countries, Senegal, Sudan and South Africa. Morphology of opisthaptoral hooks and bars and nuclear ribosomal DNA data revealed three Afrogyrodactylus species. Afrogyrodactylus girgifae sp. n. is described from the fins of the Sudanese nurse tetra, Brycinus nurse (Rüppell), and A. kingi sp. n. presents from the gill arches of the South African sharptooth tetra, Micralestes acutidens (Peters), whereas a previously undescribed Afrogyrodactylus sp. occurred on the fins of B. nurse from Senegal. All three species differ conspicuously from the only one known species of this genus, A. characinis Paperna, 1968, by the dimensions of their haptoral hard parts. Detailed morphological and molecular descriptions and comparisons are presented.