Designation of a neotype for Enteromiuspallidus (Smith, 1841), an endemic cyprinid minnow from the Cape Fold Ecoregion, South Africa

Naming the other cousin: A new goldie barb (Cyprinidae: Smiliogastrininae) from the northeast escarpment in South Africa, with proposed taxonomic rearrangement of the goldie barb group in southern Africa

A growing body of evidence indicates that the global diversity of freshwater fishes has not been fully documented. Studies of freshwater fishes that were previously thought to be morphologically variable have revealed the existence of deeply divergent lineages, with many distinct species. In southern Africa a number of Enteromius species exhibit either exceedingly wide or divided distribution patterns that should be rare for freshwater fishes with limited dispersal opportunities between river systems. One such species is the sidespot barb, Enteromius neefi. As currently defined, E. neefi has a disjunct distribution that is divided between rivers in the northeast escarpment in South Africa and Eswatini, and tributaries of the Upper Zambezi in Zambia and southern Congo in the Democratic Republic of Congo, with a large geographic gap between these two populations. With the use of molecular and morphological methods, the level of divergence between the two populations was examined, and a new species was described from the Steelpoort River in the Limpopo River system of South Africa. Findings from this study provide further evidence for a number of taxonomic problems within the goldie barbs of southern Africa, and some taxonomic rearrangements are proposed for this group.

First DNA barcode library for the ichthyofauna of the Jos Plateau (Nigeria) with comments on potential undescribed fish species

Located in the central region of northern Nigeria, the Jos Plateau covers approximately 9,400 km² with an average altitude of 1,280 m and constitutes a unique terrestrial ecoregion known as the Jos Plateau forest-grassland mosaic. The biota of the Jos Plateau include endemic elements, but very limited information is available on its ichthyofauna. This is despite the fact that the ancient plateau contributes to several large rivers spanning multiple major drainage systems including the Niger and Benue Rivers, and Lake Chad. This study provides the first species list for the fishes of the Jos Plateau based mainly on 175 DNA barcoded museum voucher specimens representing 20 species, and another three species without a DNA barcode. In total, 23 species from eight families and 17 genera were collected from the Jos Plateau including five putatively new species, four in the family Cyprinidae and one in the Clariidae. With ten species, the Cyprinidae is the most diverse fish family on the Jos Plateau, followed by Clariidae and Cichlidae, each with three species. The study also provides data on species distribution and habitat parameters including information on water chemistry that strongly suggests that selected water bodies are heavily impacted by anthropogenic activities. Urgent management steps are required to preserve the unique and diverse fish communities of the Jos Plateau and their habitats.

Diversity, distribution and extinction risk of native freshwater fishes of South Africa

Extinction risk for 101 valid species and 18 unique genetic lineages of native freshwater fishes of South Africa was assessed in 2016 following the IUCN Red List criteria. An additional five species (three new species that were described and two species that were revalidated subsequent to the 2016 assessments) were assessed in the present study. A synthesis of the outcome of the assessments of the 106 valid species and 18 genetic lineages indicates that 45 (36%) of South Africa's freshwater fish taxa are threatened (7 Critically Endangered, 25 Endangered, 13 Vulnerable). Of the remaining taxa, 17 (14%) are listed as Near Threatened, 57 (46%) are Least Concern and five (4%) are Data Deficient. More than 60% of the endemic taxa are threatened. The Cape Fold Ecoregion has the highest proportion of threatened taxa (67%) due to the existence of a unique assemblage of narrow-range endemic species. Galaxias and Pseudobarbus have the highest number of highly threatened taxa as most of the species and lineages in these genera are classified as either CR or EN. Major threats to the native freshwater fishes of the country are invasive fish species, deterioration of water quality, impoundments and excessive water abstraction, land use changes and modification of riverine habitats. Immediate conservation efforts should focus on securing remnant populations of highly threatened taxa and preventing deterioration in threat status, because recovery is rare. Accurate delimitation of species boundaries, mapping their distribution ranges, improved knowledge of pressures and long-term monitoring of population trends need to be prioritised to generate credible data for the 2026 IUCN threat status assessments and designation of important fish areas as part of the National Freshwater Ecosystem Priority Areas (NFEPA) initiative.

Allopatric differentiation in the Enteromius anoplus complex in South Africa, with the revalidation of Enteromius cernuus and Enteromius oraniensis, and description of a new species, Enteromius mandelai (Teleostei: Cyprinidae)

The chubbyhead barb, Enteromius anoplus, as currently described, is the most widely distributed freshwater fish in South Africa. The species occurs in almost all the major river systems across the country, with the exception of the small coastal drainages on the south coast. The use of a comprehensive data set of mitochondrial (mtDNA) cytochrome b (cyt b) sequences uncovered the presence of four distinct lineages or operational taxonomic units (OTUs) within E. anoplus: (a) the Gouritz lineage endemic to the Gouritz River system, (b) the Olifants lineage endemic to the Olifants-Doring River system, (c) the Orange lineage endemic to the Orange River system and (d) the Eastern Cape lineage which is distributed across six river systems from the Great Fish to the Buffalo rivers in the Eastern Cape Province of South Africa. The present study provides a new diagnosis for E. anoplus s.s. (the Gouritz lineage), revalidates Enteromius cernuus (the Olifants lineage) and Enteromius oraniensis (the Orange lineage) as distinct species. The study also provides a description for a new species, Enteromius mandelai sp. nov (the Eastern Cape lineage). E. cernuus and E. mandelai differ from both E. anoplus and E. oraniensis by having a complete lateral line (vs. an incomplete lateral line in the latter species). E. cernuus further differs from the other three species by having long maxillary barbels which reach or exceed the vertical through the middle of the eye and the lowest number of circumpendicular scales (10-12 vs. 12-16 for the other three species). E. oraniensis is distinctive from the other three species by having inconspicuous barbels. These findings add to the growing body of literature that shows that the freshwater fishes of the Cape Fold and adjacent freshwater ecoregions have narrow geographic ranges. This has ramifications for conservation planning and management, as well as the understanding of the evolutionary history of the stream fishes in these global endemic hotspots.