A new species of the cyclopoid copepod genus Ergasilus von Nordmann, 1832 is described based on adult female specimens removed from the gills of the yellow snapper Lutjanus argentiventris (Peters) and the yellowfin snook Centropomus robalito Jordan et Gilbert from a Pacific coastal system of Mexico. The new species Ergasilus davidi sp. n. has a combination of characters that includes a two-segmented first leg endopod, a three-segmented fourth leg endopod, and the presence of a single seta on the first antennular segment. These characters are shared with 14 other congeners known mainly from Brazil and North America. It differs from these other species in the armature and ornamentation of legs 1 and 4, the shape of the body, and the structure and ornamentation of the antennae. Additional characters include a maxillar basis armed with blunt teeth, distally bent maxillular setae, and naked margins of first exopodal segments of legs 2-4. Previous regional records of Ergasilus sp. from both fish species are probably assignable to E. davidi. The prevalence and intensity of infection was estimated for both teleost species and agrees to previous data. Based on other records of the genus from several other teleost species in the surveyed area and adjacent zones of the Eastern Pacific, it is presumed that the new species could have a wider range of hosts. The new species represents the first Ergasilus described from Mexican waters of the Pacific. Overall, the genus remains poorly known in Central America and Mexico.
A new myxozoan, Ceratomyxa bohari sp. n., infecting the gall bladder of two-spot red snapper, Lutjanus bohar Forsskål, in the Red Sea off Saudi Arabia, is described using light microscopy and characterised genetically. The infection was recorded as mature spores floating free in the bile. The overall prevalence of infection of the type host was 19% (67 fish infected of 360 examined), with the highest prevalence in autumn (31%; 28/90) and the lowest in winter at 12% (11/90). Mature spores are slender and slightly crescent-shaped in the frontal view, with anterior and posterior margins tapered gradually to rounded valvular tips. Spore valves are unequal with a prominent sutural line. The spore dimensions are 3-4 μm (mean 3.5 μm) in length and 16-19 μm (mean 17 μm) in thickness. Two polar capsules are spherical, equal in size, 1.5 μm in diameter. Coils of the polar filament are indiscernible. The sporoplasm is binucleated and fills nearly one third of the extracapsular space restricted to the area below the capsules. The molecular analysis based on the small subunit rDNA (SSU rDNA) sequence revealed a close relationship with majority of species of Ceratomyxa Thélohan, 1892 and phylogenetic clustering with species from different geographical location. Thus, the shorter spore of the present Ceratomyxa species and the divergence of the SSU rDNA sequences were the distinctive features that separate it from all previously described species and identified this parasite as a new species of Ceratomyxa., Lamjed Mansour, Abdel-Azeem S. Abdel-Baki, Ahmad F. Tamihi, Saleh Al-Quraishy., and Obsahuje bibliografii
Taxonomic issues within Trypanorhyncha, e.g., the inaccurate light microscopic visualisation of the hook patterns, are solvable by confocal laser scanning microscopy (CLSM). We applied CLSM imaging to study Trygonicola macropora (Shipley et Hornell, 1906) and Dollfusiella michiae (Southwell, 1929) from Neotrygon caeruliopunctata Last, White et Séret from Bali, Indonesia. To illustrate the strength and limitations of CLSM, images of Otobothrium cysticum (Mayer, 1842) and Symbothriorhynchus tigaminacantha Palm, 2004, both permanent mounts from a collection, were also processed. The CLSM created image stacks of many layers, and edited with IMARIS Software, these layers resulted in three-dimensional images of the armature patterns and internal organs of both species. BABB (benzylalcohol and benzylbenzuolate) clearing was applied to T. macropora. We conclude that trypanorhynch cestodes stained with Mayer-Schuberg's acetic carmine permanently mounted in Canada balsam are suitable for CLSM, allowing detailed analyses of museum type-material as well as freshly collected and processed worms. BABB resulted in imaging the testes in detail, suggesting other stains to be used for CLSM in trypanorhynch cestode research. Application of CLSM for studies of other cestode groups is highly recommended.
Seven species of the genus Trichodina Ehrenberg, 1838 were identified during a sampling programme of twenty freshwater fish species from approximately sixty sites in Scotland, England and Wales. Species found include: Trichodina acuta Lom, 1961 from Cyprinus carpio L., Carassius auralus L., Oncorhynchus mykiss (Walbaum), Salmo trutta L. and Phoxinus phoxinus L.; Trichodina domerguei Wallengren, 1897 from Gasterosteus aculeatuir L.; Trichodina tenuidens Faurc-Fremiet, 1944 from Gasterosteus aculeatus; Trichodina pediculus Ehrenberg, 1838 from Gasterosteus aculeatus; Trichodina modesta Lom, 1970 from Abramis brama L.; Trichodina nigra Lom, 1960 from Cyprinus carpio, Salmo trutta and Oncorhynchus mykiss', and Trichodina intermedia Lom, 1960 from Phoxinus phoxinus. Morphological variation within and between host populations and host specificity of the Trichodina species recovered are described.
During 2001 and 2002, blood smears from 37 of 120 fishes belonging to 10 species captured in the Okavango Delta region of Botswana, were found to harbour trypanosomes. These trypanosomes displayed differing staining properties, were morphometrically variable, and ranged in total length from 29.5 to 80.8 µm. Mixed populations of the smaller and larger trypanosomes were found in most fish examined. Despite variations in size and appearance, these specimens are tentatively identified as Trypanosoma mukasai Hoare, 1932, likely adding another 9 new hosts to those known for this parasite. It is possible that Trypanosoma clariense Pienaar, 1962, described from Clarias gariepinus in South Africa, is also a junior synonym of T. mukasai.
Based on light and scanning electron microscopical studies, the following five gonad-infecting species of the Philometridae (Nematoda: Dracunculoidea) are described from marine perciform fishes off the eastern coast of India (Bay of Bengal): Philometra sphyraenae sp. n. (males and females) from the pickhandle barracuda Sphyraena jello Cuvier (Sphyraenidae), Philometra gerrei sp. n. (males and females) from the whipfin silver-biddy Gerres filamentosus Cuvier (Gerreidae), Philometra otolithi sp. n. (single female) from the tigertooth croaker Otolithes ruber (Bloch et Schneider) (Sciaenidae), Philometra sp. (females) from the Belanger's croaker Johnius belangerii (Cuvier) (Sciaenidae), and Philometroides eleutheronemae sp. n. (females) from the fourfinger threadfin Eleutheronema tetradactylum (Shaw) (Polynemidae). All new species are distinguished from their congeners parasitizing gonads of marine fishes by morphological (mainly the gubernaculum structure in males and the shape and structure of the cephalic and caudal ends and of the oesophagus in females) and biometrical features. Philometra rajani Mukherjee, 1963 is considered a species inquirenda.
During an ongoing systematic survey on species diversity of myxozoans parasitising allogynogenetic gibel carp Carassius auratus gibelio (Bloch) in China, plasmodia were detected in the fins, lip, jaw, gill chamber, gill arches, operculum and oral cavity of infected fish. Combining the morphological and molecular data, the present species was identified as Myxobolus turpisrotundus Zhang, Wang, Li et Gong, 2010. Histopathological examination revealed that despite infecting different organs, M. turpisrotundus always occurred in dermis, demonstrating its affinity to this tissue. Histopathological effect of M. turpisrotundus on the host is relatively mild except parasites in the gill arches producing compression of the adipose tissue and heavy adductor muscles deformation with lymphohistiocytic infiltrates. In addition, the plasmodia in different sites were with the same complex structure arrangement: cup-like cells with unknown derivation, a thin collagenous fibril layer, areolar connective tissue, basement membrane and host epithelial cell. Ultrastructural analysis showed that the parasite has monosporic pansporoblast and sporogenesis followed the usual pattern of most of the myxosporeans., Qingxiang Guo, Yanhua Zhai, Zemao Gu, Yang Liu., and Obsahuje bibliografii
The gills of 63 specimens of the Atlantic bluefin tuna Thunnus thynnus (Linnaeus) (Osteichthyes: Scombridae) from three localities of the Mediterranean (Sardinian, Tyrrhenian and Levantine Seas) were examined for metazoan parasites. The parasite fauna of T. thynnus from the Sea of Sardinia included 11 species: five didymozoid trematodes, three capsalid and one hexostomid monogeneans, and one caligid and one pseudocycnid copepods. Four didymozoids were found in fish from the Levantine Sea and only one didymozoid was recorded in fish from the Tyrrhenian Sea. Dividing the hosts into four size-groups (small, medium-sized, large and extra large), the pairwise comparison of prevalence and mean abundance of the new and literary data) showed differences according to host size. The differences in the composition of the parasitic faunas and in the prevalence of parasites, observed between the small tunas from the Tyrrhenian Sea and the medium-sized tunas from the Adriatic Sea, Levantine Sea and the North-East (NE) Atlantic Ocean, indicated that these groups form discrete units. The parasite fauna of the large tunas from the Sea of Sardinia is the richest among the bluefin tuna populations of the Mediterranean and the NE Atlantic, due to the presence of species not found elsewhere in bluefin tunas, such as Caligus coryphaenae Steenstrup et Lütken, 1861, Capsala magronum (Ishii, 1936) and C. paucispinosa (Mamaev, 1968). This fact and the prevalence of some parasites of this group (lower than those of medium-sized fish from the NE Atlantic and higher than the small and medium-sized tunas from the Mediterranean) suggest that the large-sized tuna group in the western Mediterranean is formed by Mediterranean resident tunas (poorly infected), and by tunas migrating from the Atlantic Ocean (heavily infected).
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.
The viviparous gyrodactylid genus Macrogyrodactylus Malmberg, 1957 is endemic to Africa, composed of nine species from hosts of four freshwater fish families, including catfishes (Siluriformes: Clariidae). Three species, Macrogyrodactylus clarii Gussev, 1961; M. congolensis (Prudhoe, 1957) and M. karibae Douëllou et Chishawa, 1995, are primarily known to parasitise the African sharptooth catfish Clarias gariepinus (Burchell) in various African countries. From November 2017 to September 2019, a total of 184 individuals of C. gariepinus were collected from selected localities in southern Africa and their skin, fins and gills were surveyed for monogeneans. Three species of Macrogyrodactylus (M. clarii, M. congolensis and M. karibae) were found parasitising C. gariepinus from five localities in South Africa and Zambia. Overall prevalence was 50% to 100% with intensities of up to 109 parasites per host individual. New locality records in southern Africa, morphological observations and additional molecular data on the complete Internal Transcriber Spacer (ITS-1-5.8S-ITS-2) regions of the rDNA gene for the three gyrodactylid species are presented in this study.