A revision of the genus Astatoreochromis (Teleostei, Cichlidae), East-Africa

A taxonomic revision of the cichlid genus Astatoreochromis is presented. Eighteen meristic and 23 morphometric measurements were taken on 185 individuals, including type specimens. While fin counts separate populations from the Lake Victoria region (Astatoreochromis alluaudi) from those of the Rusizi and Malagarazi rivers in the Lake Tanganyika basin (A. vanderhorsti and A. straeleni respectively), clear differentiation was not detected between the latter two. Mann-Whitney U-tests on specimens of comparable size from the two Tanganyika populations revealed significant differences in specimens 75 mm SL and Astatoreochromis vanderhorsti is herein considered a junior synonym of A. straeleni. A redescription of the two valid species of Astatoreochromis, A. alluaudi and A.straeleni, is provided

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

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 are described in the present study. These results highlight the species diversity of this parasite genus in the Congo Basin.Peer reviewe

Multiple independent colonizations into the Congo Basin during the continental radiation of African Mastacembelus spiny eels

AIM: There has been recent interest in the origin and assembly of continental biotas based on densely sampled species-level clades, however, studies from African freshwaters are few so that the commonality of macroevolutionary patterns and processes among continental clades remain to be tested. Within the Afrotropics, the Congo Basin contains the highest diversity of riverine fishes, yet it is unclear how this fauna was assembled. To address this, and the diversification dynamics of a continental radiation, we focus on African Mastacembelus spiny eels. LOCATION: Afrotropical freshwaters. METHODS: The most complete molecular phylogeny to date was reconstructed for African spiny eels. Divergence times were estimated applying a Bayesian relaxed clock comparing fossil and geological calibrations across nuclear and mitochondrial trees. Biogeographic reconstructions, applying a dispersal–extinction–cladogenesis model and lineage diversification dynamics were examined. RESULTS: Spiny eels originated in Asia and colonized Africa c. 15.4 Ma (95% HPD: 23.9–8.8 Ma) from which their subsequent radiation across the Afrotropics was best fitted by a constant rate model. Ancestral state estimation identified multiple colonization events into the Congo Basin, whereas all other regions were likely to have been colonized once indicating considerable geographic constraints. Application of the fossil calibration gave similar age estimates across datasets, whereas a geological calibration estimated considerably older nuclear divergences. MAIN CONCLUSIONS: Despite profound environmental events during the evolutionary history of the group, there is no evidence for rapid lineage diversification. This finding supports several recent studies on tropical continental radiations that contrast to the common pattern of density-dependent diversification. We further show that dispersal has occurred into, as well as out of the Congo Basin, indicating the importance of this region in the generation of biodiversity

Six new dactylogyrid species (Platyhelminthes, Monogenea) from the gills of cichlids (Teleostei, Cichliformes) from the Lower Congo Basin

The Lower Congo Basin is characterized by a mangrove-lined estuary at its mouth and, further upstream, by many hydrogeographical barriers such as rapids and narrow gorges. Five localities in the mangroves and four from (upstream) left bank tributaries or pools were sampled. On the gills of Coptodon tholloni, Coptodon rendalli, Hemichromis elongatus, Hemichromis stellifer and Tylochromis praecox, 17 species of parasites (Dactylogyridae & Gyrodactylidae, Monogenea) were found, eight of which are new to science. Six of these are herein described: Cichlidogyrus bixlerzavalai n. sp. and Cichlidogyrus omari n. sp. from T praecox, Cichlidogyrus calycinus n. sp. and Cichlidogyrus polyenso n. sp. from H. elongatus, Cichlidogyrus kmentovae n. sp. from H. stellifer and Onchob-della ximenae n. sp. from both species of Hemichromis. On Cichlidogyrus reversati a ridge on the accessory piece was discovered that connects to the basal bulb of the penis. We report a putative spillback effect of the native parasites Cichlidogyrus berradae, Cichlidogyrus cubitus and Cichlidogyrus flexicolpos from C. tholloni to the introduced C. rendalli. From our results, we note that the parasite fauna of Lower Congo has a higher affinity with the fauna of West African and nearby freshwater ecoregions than it has with fauna of other regions of the Congo Basin and Central Africa.Peer reviewe

К вопросу о табулировании функций распределения отказов

Проведена перепараметризация основных строго вероятностных функций распределения отказов: экспоненциального распределения, логарифмически нормального распределения и распределения Вейбулла. Разработаны таблицы функций распределения отказов и примеры их использования для решения некоторых задач по надежности.Проведено перепараметризацію основних строго ймовірнісних функцій розподілів відмов: експоненційного розподілу, логарифмічно нормального розподілу, розподілу Вейбулла. Розроблено таблиці функцій розподілів відмов та приклади їх використання для рішення деяких задач з надійності.The reparametrization of the basic strictly probabilistic functions of refusals distribution: exponential distributions, logarithmically normal distribution and distribution Weibull are carried out. Tables of refusals distribution functions and examples of their use for the decision of some tasks on reliability are developed

A re-evaluation of the species-level diversity within the catfish genus Auchenoglanis (Siluriformes: Claroteidae)

The taxonomic history of the African catfish genus Auchenoglanis includes eight nominal species, with two of these, Auchenoglanis biscutatus and Auchenoglanis occidentalis, being recognized as valid by most authors. The validity of all eight species was recently established based on mainly pigmentation-related characters and the shape of the premaxillary tooth plates. As these results opposed previous works but lacked any mention of these, the species diversity in the genus was re-evaluated based on biometric, meristic and other morphological data. It reconfirms the status of only two valid species within the genus. Auchenoglanis occidentalis ranks among the African fish species with very large distribution areas, being present from Senegal to Tanzania. Auchenoglanis biscutatus is distinguished from A. occidentalis by a postorbital head length that is greater than the preorbital head length, an adipose fin that rises abruptly, and a maxillary barbel with a tip not darker than the head colour

An updated checklist of the ichthyofauna of the Mono River basin (Benin and Togo: West Africa).

peer reviewedIn order to evaluate the impact of anthropogenic changes, such as the future construction of a dam at Adjarala, on the fish diversity of the Mono rRver basin, a list of the ichthyofauna of this basin has been compiled. A total of 60 native and one introduced species, belonging to 40 gebera and 23 families are rapported. The families Cyprinidae and Cichlidae are the best represented. Of the 60 native species recorded, three are typically marine, while five others are estuarine. The present study shows that the species diversity of the lower Mono is most probably underestimated

Contribution to the knowledge of the ichthyofauna in the Inkisi River, Lower Congo (RDC)

L’étude de la composition et de la distribution de la faune ichtyologique de la partie congolaise de la rivière Inkisi a permis d’inventorier 61 espèces réparties en 37 genres appartenant à 15 familles. Les Cyprinidae sont les mieux représentés avec 15 espèces. Les Mormyridae, Cichlidae et Clariidae viennent ensuite avec respectivement 11, 9 et 7 espèces. La composition spécifique des communautés des poissons est différente, du cours supérieur vers l’aval. Le profil longitudinal de cette partie de l’Inkisi est caractérisé par la présence de trois chutes qui sont, de l’aval vers l’amont : la chute de Mantumpu (8 m de hauteur) à l’entrée de l’Inkisi dans le fleuve Congo, la chute de Zongo (58 m) à 6 km du confluent et la chute de Sanga (24 m) à 10 km de la chute de Zongo. La présence de ces chutes sur le cours de la rivière semble avoir influencé l’ichtyofaune et pourrait même être à l’origine du nombre important d’espèces endémiques en amont. Si l’on s’en tient au cours principal, la différence entre la richesse spécifique en amont et celle en aval n’est pas significative, probablement à cause de la morphologie du bassin. La richesse et la composition spécifique de la partie comprise entre les deux chutes (Zongo et Sanga) ne diffèrent pas de celles de l’amont de la chute de Sanga. Toutefois, cette composition est fort différente de celle de la zone tout en aval