First record of monogenean fish parasites in the Upper Lufira River Basin (Democratic Republic of Congo): dactylogyrids and gyrodactylids infesting Oreochromis mweruensis, Coptodon rendalli and Serranochromis macrocephalus (Teleostei: Cichlidae).

BACKGROUND: Monogenean parasites have never been formally reported on fishes from the Lufira River Basin. In this context, we decided to record the monogenean parasite fauna of three cichlid species found in the Upper Lufira River Basin for the first time by inventorizing their diversity (species composition) and analysing their infection parameters (prevalence, mean intensity and abundance). METHODS: The African cichlid fishes Oreochromis mweruensis, Coptodon rendalli and Serranochromis macrocephalus were selected for the study, given their economic value and their abundance in the Upper Lufira River Basin. Monogeneans were isolated from the gills and stomach, mounted on glass slides with either Hoyer's medium or ammonium picrate-glycerin for identification under a stereomicroscope, based on morphological analysis of genital and haptoral hard parts. Indices of diversity and infections parameters were calculated. RESULTS: A total of 13 gill monogenean parasite species (Cichlidogyrus dossoui, C. halli, C. karibae, C. mbirizei, C. papernastrema, C. quaestio, C. sclerosus, C. tiberianus, C. tilapiae, C. zambezensis, Scutogyrus gravivaginus, S. cf. bailloni and Gyrodactylus nyanzae) and one stomach monogenean (Enterogyrus malmbergi) were identified. A species richness (S) of 10 for O. mweruensis, S = 6 for C. rendalli and S = 2 for S. macrocephalus was recorded. Five parasite species were reported to be common amongst O. mweruensis and C. rendalli. According to cichlid species, the most prevalent parasite species was C. halli (prevalence [P] = 80.9%) on O. mweruensis, C. dossoui (P = 92.9%) on C. rendalli and C. karibae and C. zambezensis (both P = 9.1%) on S. macrocephalus. The parasite species with the highest mean intensity (MI) were G. nyanzae (MI = 8.7) on O. mweruensis, C. papernastrema (MI = 17.1) on C. rendalli and C. karibae (MI = 15) on S. macrocephalus. The findings indicate new host ranges for five parasites species (C. quaestio, S. cf. bailloni, E. malmbergi on O. mweruensis, C. halli on C. rendalli and C. karibae on S. macrocephalus) as well as new geographical records for all of them as they are recorded for the first time in the Lufira River Basin. CONCLUSIONS: This study highlighted the richness of monogenean communities in the Upper Lufira River Basin and is a starting point for future helminthological studies, such as on the use of fish parasites as indicators of anthropogenic impacts.

A new Parakneria Poll 1965 (Gonorhynchiformes: Kneriidae), 'Mikinkidi' from the Upper Lufira Basin (Upper Congo: DRC): Evidence from a morphologic and DNA barcoding integrative approach.

A new species, Parakneria alytogrammus, is described from the main stream of the Upper Lufira River. This species is easily distinguished from its congeners from the Congo Basin by its unique colouration, consisting of a low number of transversal bands on each of the caudal-fin lobes, 2 (vs. 3-5) and the presence of an uninterrupted lateral mid-longitudinal black band in fresh and preserved specimens (vs. absent). In addition, the new species differs from its Upper Lualaba congeners by the narrow width of its pectoral-fin base, 4.8-5.6% LS [vs. wider, 8.2-10.1% for P. lufirae, 8.6% LS for P. damasi (holotype), and 7.6-7.9% LS for P. thysi]. Finally, it differs from the only species currently known from the Luapula-Mweru system, P. malaissei, by having a short post-dorsal distance, 36.4-36.6% LS (vs. longer, 38.6-41.1% LS ) and a short post-pelvic distance of 40.0-40.6% LS (vs. longer, 41.4-44.1% LS ). Mitochondrial DNA-haplotypes of P. alytogrammus sp. nov. form a clade, which is sister to the P. thysi clade, and from which it diverges by a genetic (Kimura 2-parameter and uncorrected p) distance of 0.7% in the COI-barcoding locus. The Upper Lufira, one of the sub-basins of the Upper Congo Basin, remains poorly explored relative to its fish fauna. In contrast, the region is well explored with regard to its mineral wealth. Unfortunately, mining exploitation is carried out in the region without proper concern for the environment. Thus, the discovery of this new species for science calls for increased protection and aquatic biodiversity exploration in this mining region.

Description of a new small-sized Synodontis species (Siluriformes: Mochokidae) that is important for local subsistence fisheries in the middle Lufira (upper Congo River, DR Congo).

Synodontis denticulatus sp. nov. is an endemic from the middle Lufira Basin and its associated tributaries and lakes. The species shows close morphological resemblance to Synodontis greshoffi and Synodontis unicolor, which are widespread Congo Basin and Bangweulu-Mweru endemic species, respectively. However, it differs from both S. greshoffi and S. unicolor by its non-villous skin (v. villous skin), strong and numerous serrations on the posterior margin of the dorsal spine (v. weak and fewer serrations), weak and few serrations on the posterior margin of the pectoral spine (v. strong and numerous serrations), relatively short maxillary barbels (v. long) and its small maximum standard length (89.1 mm LS v. 148.0 and 190.7 mm LS respectively). A DNA barcoding study (coI, mtDNA) revealed that S. denticulatus forms a distinct genetic clade with a genetic distance of 2.18% with S. greshoffi and 0.84% with S. unicolor. Synodontis denticulatus is caught regularly and abundantly as a by-catch in the gillnet fisheries in the middle Lufira lakes. Owing to its small overall size and large bony head, the species has usually no real commercial value but is an important food fish for the fishermen's families.

Description of five new rheophilic Orthochromis species (Teleostei: Cichlidae) from the Upper Congo drainage in Zambia and the Democratic Republic of the Congo.

Five new rheophilic haplochromine cichlid species are described from the Upper Congo drainage of Zambia and the Democratic Republic of the Congo: Orthochromis mporokoso sp. nov. and O. katumbii sp. nov. from the Bangwelu-Mweru ecoregion, O. kimpala sp. nov. and O. gecki sp. nov. from the Upper Lualaba ecoregion, and O. indermauri sp. nov. from the Lufubu River of the Lake Tanganyika ecoregion. Orthochromis kimpala sp. nov, O. gecki sp. nov., and O. indermauri sp. nov. are distinguished from all currently valid species of the genus Orthochromis Greenwood 1954, except for O. torrenticola (Thys van den Audenaerde 1963), by the presence of eggspots or eggspot-like maculae on the anal fin (vs. no eggspots). The three species can be easily distinguished from O. torrenticola by having three anal spines (vs. four anal spines). Moreover, all five new species can be individually distinguished from all currently known rheophilic taxa placed in the genera Orthochromis, Schwetzochromis Poll 1948 and the rheophilic species of the genus Haplochromis Hilgendorf 1888 (e.g. H. bakongo Thys van den Audenaerde 1964, H. snoeksi Wamuini Lunkayilako Vreven 2010, H. vanheusdeni Schedel et al. 2014) either based on meristic values, morphometric distances and colouration patterns, or on a combination of them.