Six new species of Cichlidogyrus Paperna, 1960 (Platyhelminthes: Monogenea) from the gills of cichlids (Teleostei: Cichliformes) from the Lomami River Basin (DRC: Middle Congo)

Abstract

Background: Monogenea van Beneden, 1858 is a group of parasitic flatworms, commonly found infecting bony fish. Several genera, such as Cichlidogyrus Paperna, 1960, are reported to include potential pathogenic species that can negatively impact aquaculture fish stocks. They can switch from introduced to native fish and vice versa. In Africa (and all over the world), fish species belonging to Cichlidae are often kept in aquaculture and represent a major source of food. Thus, research on the biodiversity and occurrence of monogenean species on these fish is of importance for aquaculture and conservation. The present study is a survey of the diversity of species of Cichlidogyrus in the south of the Democratic Republic of the Congo (DRC) on three cichlid species: Orthochromis sp. 'Lomami' , Serranochromis cf. macrocephalus, and Tilapia sparrmanii Smith, 1840. Methods: Specimens of Cichlidogyrus were isolated from the gills and mounted on glass slides with Hoyer's medium. The genital and haptoral hard parts were measured and drawn using interference contrast. Results: In total, six species of Cichlidogyrus were found, all new to science: C. bulbophallus n. sp. and C. pseudozambezensis n. sp. on S. cf. macrocephalus, C. flagellum n. sp. and C. lobus n. sp. on T. sparrmanii, C. ranula n. sp. on S. cf. macrocephalus and Orthochromis sp. 'Lomami' , and C. maeander n. sp. found on Orthochromis sp. 'Lomami' and T. sparrmanii. The first four species are considered to be strict specialists, C. ranula n. sp. an intermediate generalist and C. maeander n. sp. a generalist. These parasite species show morphological similarities to species found in the Lower Guinea and Zambezi ichthyofaunal provinces, which might be explained by past river capture events between river systems of the Congo Province and both these regions. Conclusions: Serranochromis cf. macrocephalus and Orthochromis sp. 'Lomami' can harbour respectively three and two species of Cichlidogyrus, all described in this study. Tilapia sparrmanii can harbour seven species, of which three

Antiparasitic and Antibacterial Functionality of Essential Oils: An Alternative Approach for Sustainable Aquaculture

“…Cichlidogyrus is the parasite genus that occurs naturally in cichlid fish and has the most species among gill parasites, with its 131 different species known [80]. Scutogyrus species can also be dominant in the winter season among fish belonging to the Cichlidae family [81].…”

Somewhere I belong: phylogeny and morphological evolution in a species-rich lineage of ectoparasitic flatworms infecting cichlid fishes

“…The copyright holder for this preprint this version posted March 22, 2021. ; https://doi.org/10.1101/2021.03.22.435939 doi: bioRxiv preprint EVOLUTION OF A SPECIES-RICH LINEAGE OF PARASITES thickening at the first turn in the proximal half and frequently displays a folded back (C. paganoi, C. vexus), straight and pointy (C. guirali), or hook-like (C. bilongi, C. douellouae, C. ergensi, C. gallus, C. legendrei, C. microscutus) distal end, or sometimes additional terminations resulting in a furcate ending with two (C. aegypticus, C. agnesi, C. anthemocolpos, C. bouvii, C. cubitus, C. flexicolpos, C. lemoallei, C. louipaysani, C. ouedraogoi, C. testificatus, C. thurstonae, C. tiberianus) (Geraerts et al 2020). However, all of these species differ from the confirmed clade members as follows.…”

Four new species ofCichlidogyrus(Platyhelminthes, Monogenea, Dactylogyridae) from Lake Victoria haplochromine cichlid fishes, with the redescription ofC. bifurcatusandC. longipenis

“…is that, while the relative lengths of hook pairs III to VII were previously often considered together [36, 59], in this species, pair V is clearly longer than the others. Size differences within hook pairs III to VII have also been reported from recently discovered congeners in the Congo river basin [18, 10]. In agreement with Rahmouni et al [42] and Geraerts et al [10], this further illustrates that the different haptor configurations proposed for the classification of species of Cichlidogyrus into four morphotype groups, mostly based on West African representatives (see [40, 59]) cannot accommodate all the recently described species from Central, East and Southern Africa.…”

“…Size differences within hook pairs III to VII have also been reported from recently discovered congeners in the Congo river basin [18, 10]. In agreement with Rahmouni et al [42] and Geraerts et al [10], this further illustrates that the different haptor configurations proposed for the classification of species of Cichlidogyrus into four morphotype groups, mostly based on West African representatives (see [40, 59]) cannot accommodate all the recently described species from Central, East and Southern Africa. Phylogenetic analyses with increased species coverage are needed to re-evaluate to what extent the relative length of the haptoral hooks is systematically informative.…”

“…Pending a global revision of the species-rich genus Cichlidogyrus using genetic data (130 valid species described today: [37, 42, 43, 10]), the species belonging to this genus are grouped together by morphological similarities to facilitate their systematic analysis [40, 59]. Closely related species within the genus can be grouped by the morphology of their reproductive apparatus, whereas genera and subgeneric categories are more easily grouped by the morphology of their haptoral hard parts, one of the first criteria being the relative length of the hooks (see [36, 37]).…”