A total of 22 specimens of whiting Merlangius merlangus (L.) (Teleostei, Gadidae) from the northern Øresund, Denmark were examined for Myxosporea. Zschokkella hildae Auerbach, 1910 (Myxidiidae), Gadimyxa sp. (Parvicapsulidae) and a species of Bipteria occurred in the renal tubules of 9%, 18% and 68% whiting, respectively. Immature spores of the Bipteria species are very similar to spores of Myxoproteus formosus Kovaleva et Gaevskaya, 1979 originally described from the urinary system of whiting from the Celtic Sea. We therefore consider Bipteria sp. from whiting in Denmark conspecific with M. formosus and propose Bipteria formosa (Kovaleva et Gaevskaya, 1979) comb. n. The spore of Bipteria formosa is described in detail and compared with other Bipteria spp. The phylogenetic position of B. formosa, based on partial 18S rDNA sequences, is closest to Leptotheca fugu Tun, Yokoyama, Ogawa et Wakabayashi, 2000 and the Sphaerosporidae.
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.