A review of the tumultuous history of the alpha- and genus-level taxonomy of the hexaploid African Torini, i.e. Labeobarbus s.l. (synonym: Varicorhinu

Heteromormyrus Steindachner, 1866, a genus of Mormyridae (Teleostei: Osteoglossomorpha), has been monotypic since the description of Heteromormyrus pauciradiatus (Steindacher, 1866) from a single specimen. No type locality other than “Angola” was given and almost no specimens have been subsequently identified to this species. In order to investigate the relationship of this taxon to fresh specimens collected in Angola and elsewhere, whole genome paired-end sequencing of DNA extracted from the holotype specimen of Heteromormyrus pauciradiatus was performed and a nearly complete mitogenome assembled from the sequences obtained. Comparison of cytochrome oxidase I and cytochrome b sequences from this mitogenome to sequences from recently collected material reveal that Heteromormyrus pauciradiatus is closely related to specimens identified as Hippopotamyrus ansorgii (Boulenger, 1905), Hippopotamyrus szaboi Kramer, van der Bank & Wink, 2004, Hippopotamyrus longilateralis Kramer & Swartz, 2010, as well as to several undescribed forms from subequatorial Africa collectively referred to in the literature as the “Hippopotamyrus ansorgii species complex” and colloquially known as “slender stonebashers.” Previous molecular phylogenetic work has shown that these species are not close relatives of Hippopotamyrus castor Pappenheim, 1906, the type species of genus Hippopotamyrus Pappenheim, 1906 from Cameroon, and are thus misclassified. Hippopotamyrus ansorgii species complex taxa and another species shown to have been misclassified, Paramormyrops tavernei (Poll, 1972), are placed in genus Heteromormyrus and one genetic lineage from the Kwanza and Lucala rivers of Angola are identified as conspecific Heteromormyrus pauciradiatus. Three additional new combinations and a synonymy in Mormyridae are introduced. The morphological characteristics and geographical distribution of the genus Heteromormyrus are reviewed. The electric organ discharges (EODs) of Heteromormyrus species are to be treated in a separate study.

The identity of Barbus capensis, as described by Andrew Smith (1841), is reviewed following a careful examination of the lectotype in the Natural History Museum, London. Evidence shows clearly that it represents a specimen of the Berg-Breede River whitefish or ‘witvis’ and not the species known as the Clanwilliam yellowfish, to which it was attributed until recently. The original illustration of the species is shown to be a composite of these two different species. A replacement name for the Clanwilliam yellowfish is drawn from the earliest described synonym, Labeobarbus seeberi (Gilchrist & Thompson, 1913). Following widespread recognition that the genus Barbus Daudin, 1805 does not occur in sub-Saharan Africa, the generic status of the Berg-Breede River whitefish (witvis) and other tetraploid cyprinines of southern Africa is reviewed, taking genetic and morphological characters into account. Five distinct lineages, each representing a genus, are recognized, including the genera Pseudobarbus Smith, 1841 and Cheilobarbus Smith, 1841, and three new genera described herein: Amatolacypris gen. nov., Sedercypris gen. nov. and Namaquacypris gen. nov.

Background: Monogenea van Beneden, 1858 is a group of parasitic flatworms, commonly found infecting bony fish. Several genera, such asCichlidogyrusPaperna, 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 ofCichlidogyrusin the south of the Democratic Republic of the Congo (DRC) on three cichlid species:Orthochromissp. ‘Lomami’,Serranochromiscf.macrocephalus, andTilapia sparrmaniiSmith, 1840.Methods: Specimens ofCichlidogyruswere 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 ofCichlidogyruswere found, all new to science:C. bulbophallusn. sp. andC. pseudozambezensisn. sp. onS.cf.macrocephalus,C. flagellumn. sp. andC. lobusn. sp. onT. sparrmanii,C. ranulan. sp. onS.cf.macrocephalusandOrthochromissp. ‘Lomami’, andC. maeandern. sp. found onOrthochromissp. ‘Lomami’ andT. sparrmanii. The first four species are considered to be strict specialists,C. ranulan. sp. an intermediate generalist andC. maeandern. 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: Serranochromiscf.macrocephalusandOrthochromissp. ‘Lomami’ can harbour respectively three and two species ofCichlidogyrus, all described in this study.Tilapia sparrmaniican 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.

A morphological case study, including 25 meristics and 31 measurements of 37 Labeobarbus specimens from the Inkisi basin, Lower Congo, is presented. Two groups of specimens express either Labeobarbus-like (rubberlip) or Varicorhinus-like (chiselmouth) mouth phenotypes and a third group is morphologically intermediate. Rubberlip and chiselmouth specimens differ significantly from each other in some meristics and morphometrics, and all three phenotypes of this Inkisi complex form a strongly supported monophylum based on mitochondrial (COI) and nuclear (AFLP) DNA phylogenetic inferences. Tree-based analyses designed to differentiate between polymorphism, incipient speciation and hybridization scenarios, in combination with multivariate PCA of AFLP multilocus genotypes, revealed substantial, non-random genomic variation, which correlated strongly with the three major mouth phenotype groups and favours a scenario of secondary hybridization between primarily distinct parental lineages. Consequently, the two distinct mouth phenotypes are described taxonomically as species taxa and the various morphological intermediates are characterized as hybrid phenotypes. This study suggests that a new interpretation of the alpha-level taxonomy of the hexaploid Torini is necessary. These proposed changes are highlighted and discussed for African Torini. A typology of Labeobarbus mouth phenotypes was developed, which will be useful for future studies.