A redescription of the adult male and praniza of Gnathia africana Barnard, 1914 is provided from material collected at three localities along the South African coast and from syntypes and other material deposited by the original author. This redescription is based on light and scanning electron microscopy.
A redescription of the adult male of Caecognathia cryptopais (Barnard, 1925) is provided from syntypes and other material deposited in the South African Museum. The generic status of Caecognathia cryptopais is also revised. This redescriplion is based on light and scanning electron microscopy.
Trichodina centrostrigeata Basson, Van As et Paperna, 1983 from Oreochromis mossambicus (Peters) and O. niloticus (Linnaeus) from different host populations from Argentina, Mexico and South Africa was reviewed. Although T. centrostrigeata has a distinct denticle structure that makes morphological taxonomic inferences uncomplicated, variation of the denticles within and among individuals and populations were still observed. While traditional taxonomy of mobilines is heavily reliant on morphometrics, and recently even more so on molecular analysis, this paper proposes the use of geometric morphometry, specifically elliptical Fourier analysis, to address morphological conflicts that arise when comparing different populations. By applying this technique, combined with traditional taxonomy, it was found that T. centrostrigeata in this study can be grouped into two separate morphotypes, the first (type a) from aquaculture farms in Argentina and Mexico and the second (type b) from a natural habitat in Glen Alpine Dam, South Africa. This study supports the validity of geometric morphometry as an additional technique to distinguish not only between species but also evolutionary plasticity of the same species from different localities and habitats.
Current records of marine myxozoans from the coast of Africa are limited to the descriptions of 52 species from mostly Senegal, with a few from Tunisia and southern Africa. Between 1998 and 2000 several intertidal fishes from the southern Cape coast of South Africa were examined for the presence of myxozoan infections. Three new species, Ceratomyxa dehoopi sp. n., C. cottoidii sp. n. and C. honckenii sp. n. were identified from the gall bladders of Clinus superciliosus L., C. cottoides Valenciennes and Amblyrhynchotes honckenii (Bloch), respectively. A fourth new species Henneguya clini sp. n. was also identified from the gills and gill arches of C. superciliosus.
Haematophagous larvae of a gnathiid isopod were collected from the gills, nares and buccal cavity of a single leopard catshark Poroderma pantherinum (Smith, 1838) at Jeffreys Bay and five puffadder shysharks Haploblepharus edwardsii (Voight, 1832) and one blackspotted electric ray Torpedo fuscomaculata Peters, 1855, at the De Hoop Nature Reserve on the South African south coast. Larvae were kept in fresh seawater until their moult into adult stages. The morphology of the adult males did not conform to that of any known species and they are therefore described as Gnathia pantherina sp. n. The descriptions of the adult male, female and praniza larva are based on light and scanning electron microscopy observations. Characteristic features of this species include the large size of all the final life-cycle stages, the deeply divided mediofrontal process of the male, the morphology of the pylopods and maxillipedes of the female, and the number of teeth on the mandibles (eight) and maxillules (seven) of the praniza larvae.
Laboratory work was conducted to elucidate the life cycle of the South African gnathiid isopod, Gnathia africana Barnard, 1914. The natural fish hosts of this temporary parasite, the super klipfish Clinus superciliosus (Linnaeus, 1758), were exposed to gnathiid larvae in the laboratory. It was found that G. africana has three larval stages, consisting of three unfed (zuphea) and three fed (praniza) stages. First-, second- and third-stage zuphea larvae took an average of 2 h 18 min, 2 h 43 min and 10 h 8 min respectively to complete their feeding and the first- and second-stage praniza moulted at 8 and 10 days respectively into the next zuphea stage. Three to six days after its last blood meal, the sex of the third and final praniza stage could be determined by the presence of either a testis or two ovaries in the dorsal pereon. Male larvae moulted into adult males between 8 and 10 days post feeding. Female larvae moulted at approximately 17 days into adult females. Fertilisation of the eggs by the male took place within 24 hours of completion of the female moult. The development of the embryos and subsequent release of the young larvae between 15 and 23 days post fertilisation completed the cycle. This entire cycle took approximately 62 days in water temperatures of 20-25°C.
Fieldwork was conducted in 1998 and 1999 in the Okavango River and Delta and a total of 275 fishes representing 31 species were examined for the presence of myxosporean parasites. A total of seven myxosporeans of the genus Myxobolus Bütschli, 1882 were found infecting the fishes. Two new species namely Myxobolus etsatsaensis sp. n. from Barbus thamalakanensis Fowler, 1935 and M. paludinosus sp. n. from Barbus paludinosus Peters, 1852 are described. Myxobolus africanus Fomena, Bouix et Birgi, 1985, M. camerounensis Fomena, Marqués et Bouix, 1993, M. hydrocyni Kostoïngue et Toguebaye, 1994, M. nyongana (Fomena, Bouix et Birgi, 1985) and M. tilapiae Abolarin, 1974 are recorded for the first time in Botswana and descriptions of these species are provided.
During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.
A redescription of the female of the temporary fish parasite, Gnathia africana Barnard, 1914 is provided from specimens reared from final-stage G. africana praniza larvae collected from their intertidal fish hosts along the south coast of southern Africa. It differs from other known gnathiid females in the shape of the frontal border and the number and basic form of pylopod articles. This redescription aims to establish a format for future descriptions and redescriptions of gnathiid females.
During parasitological surveys in the Okavango Delta and Panhandle in Botswana, two species of climbing perches belonging to the family Anabantidae were investigated for ectoparasites. The fishes were the blackspot climbing perch, Microctenopoma intermedium (Pellegrin) and the manyspined climbing perch, Ctenopoma multispine Peters. Five trichodinid species were found from the skin, fins and gills of these anabantids. One is a known species, i.e., Trichodina microspina Van As et Basson, 1992, for which a comparative description is provided. Four other species are described as new species using silver impregnation, i.e., Trichodina labyrinthipiscis sp. n., Trichodina anabantidarum sp. n., Tripartiella microctenopomae sp. n., and Tripartiella ctenopomae sp. n.