This study used phylogenetic analyses of mitochondrial cytochrome b sequences to investigate genetic diversity within three broadly co-distributed freshwater fish genera (Galaxias, Pseudobarbus and Sandelia) to shed some light on the processes that promoted lineage diversification and shaped geographical distribution patterns. A total of 205 sequences of Galaxias, 177 sequences of Pseudobarbus and 98 sequences of Sandelia from 146 localities across nine river systems in the south-western Cape Floristic Region (South Africa) were used. The data were analysed using phylogenetic and haplotype network methods and divergence times for the clades retrieved were estimated using *BEAST. Nine extremely divergent (3.5–25.3%) lineages were found within Galaxias. Similarly, deep phylogeographic divergence was evident within Pseudobarbus, with four markedly distinct (3.8–10.0%) phylogroups identified. Sandelia had two deeply divergent (5.5–5.9%) lineages, but seven minor lineages with strong geographical congruence were also identified. The Miocene-Pliocene major sea-level transgression and the resultant isolation of populations in upland refugia appear to have driven widespread allopatric divergence within the three genera. Subsequent coalescence of rivers during the Pleistocene major sea-level regression as well as intermittent drainage connections during wet periods are proposed to have facilitated range expansion of lineages that currently occur across isolated river systems. The high degree of genetic differentiation recovered from the present and previous studies suggest that freshwater fish diversity within the south-western CFR may be vastly underestimated, and taxonomic revisions are required.

1. Mediterranean climate regions are globally recognized as hotspots of endemism in fishes; however, these unique assemblages are increasingly threatened by human mediated impacts including water abstraction, damming and non-native species introductions.2. The Cape Fold aquatic ecoregion (CFR) of South Africa supports an assemblage of range-restricted endemic freshwater fishes, the majority of which are conservation priorities because they are under severe threat of extinction. Effective conservation and management are constrained by the lack of readily available information on this imperilled group of fishes because research efforts over the last century have been temporally disjointed and relatively uncoordinated.3. This review provides an exhaustive appraisal of published literature on the taxonomy, biogeography, life history, ecology and physiology of freshwater fishes in the CFR, and the human impacts that affect them. Its aim is to direct future research needs for effective management and conservation of this imperilled group. 4. Only 103 peer-reviewed articles on CFR fishes were recorded and the majority of available research is on taxonomy and biogeography (40.8%), followed by ecological investigations (22.3%), conservation (19.4%) and human impacts (17.5%). 5.Despite a plethora of studies on taxonomy and biogeography, recent genetic evidence suggests that fish diversity in the CFR has been severely underestimated and requires urgent attention. Human impacts severely threaten the existence of many native CFR fishes and require further study. Information on the biology and ecology of CFR fishes is limited to studies on selected species; of particular note is the lack of physiological information which is particularly pertinent given projected climate change scenarios.

A new cyprinid species, Pseudobarbus skeltoni sp. nov, is described from material recently collected in the upper Riviersonderend River (a major tributary of the Breede River system) and the Krom River (a tributary of the Molenaars River in the upper Breede River) in the Cape Floristic Region of South Africa. The new species is readily distinguished from congeners, except P. burgi and P. burchelli, by having two pairs of prominent oral barbels. Pseudobarbus skeltoni can be distinguished from P. burgi and P. burchelli by the following combination of characters: distinctive terminal (vs. subterminal) mouth in adults; mouth inferior in sub-adults and young adults of P. skeltoni but lower lips are unretracted (vs. retracted) and lack a distinct cartilaginous plate; snout prominent; more slender head (head depth 64.2% of HL, vs. 70.1% of HL in P. burchelli and 74.1% of HL in P. burgi); and a longer head relative to standard length (30.5 % vs. 26.8% in P. burchelli and 25.8% in P. burgi). The new species attains the largest size of any Pseudobarbus. The restricted distribution and the small remaining population sizes of P. skeltoni indicate that this species is highly threatened and requires immediate conservation attention.

Many rivers in southern Africa are increasingly threatened by accelerating geomorphological degradation due to unsustainable agricultural practices and deforestation. Thus, there is a critical need for biological indicators of morphological degradation in running waters. This study analysed the composition and abundance of Trichoptera taxa from 32 sites from rivers in eastern and northwestern Zimbabwe in relation to geomorphological and land use parameters. Redundancy analysis (RDA) and Spearman's rank correlation analysis revealed that species in the genera Anisocentropus, Dyschimus, Lepidostoma, Leptocerina, Athripsodes, Parasetodes, Aethaloptera, Hydropsyche and Polymorphanisus were restricted to undisturbed forested sites, suggesting that these Trichoptera taxa may be used as indicators of structural degradation in watercourses. A species in the genus Hydroptila was the only Trichoptera taxon that showed a statistically significant numerical abundance at disturbed agricultural sites.

Aim A river hierarchy model has been proposed for stream‐dwelling taxa, where genetic structure is expected to reflect geographical proximity and connectivity of river systems. However, many exceptions and deviations from this model have been detected. The present study tested three biogeographical hypotheses (River Hierarchy, Palaeoriver Systems and Interdrainage Dispersal) to assess how a recently identified galaxiid, Galaxias sp. ‘nebula’, came to have a wide distribution across multiple currently isolated river systems in the Cape Floristic Region of South Africa. Location Seventeen river systems in the Cape Floristic Region at the southern tip of Africa. Methods We analysed mitochondrial cytochrome c oxidase subunit I and cytochrome b sequences from across the entire distribution of Galaxias sp. ‘nebula’ and compared divergence times between populations with known geological and climatic events to explain the observed geographical patterns of genetic diversity. Results The data revealed historical divergence between the Olifants, Berg and southward‐draining river systems. The phylogeographical analyses revealed that range expansion occurred across currently isolated river systems, with some haplotypes being shared between geographically distant river systems. Molecular dating revealed recent divergence times between populations from isolated river systems (c. 4000–1,200,000 years ago). Main conclusions The phylogeographical pattern of Galaxias sp. ‘nebula’ indicates that drainage basin boundaries have historically not played a dominant long‐term role in structuring this lineage. River captures are not widespread and frequent enough to explain the observed genetic patterns. Galaxias sp. ‘nebula’ has been able to disperse between proposed palaeoriver systems. Interdrainage dispersal via episodic freshwater connections during periods of increased rainfall during the Pleistocene and Holocene epochs seems to have played an important role in allowing this lineage to attain and maintain its wide contemporary distribution.

Temporary rivers within the NyaodzaGachegache subcatchment in northwestern Zimbabwe were investigated to examine the role of flow permanence and habitat structure on macroinvertebrate community composition. Macroinvertebrate communities of intermittent and ephemeral rivers displayed significant differences in the number of taxa, macroinvertebrate abundance, Shannon and Simpson diversity indices and in size class structure. Intermittent sites were characterised by higher numbers of taxa, diversity and Ephemeroptera and Trichoptera richness compared to ephemeral sites. The fauna of ephemeral sites was dominated by a single taxon (Afrobaetodes) (Ephemeroptera, Baetidae) whilst larger sized taxa (e.g. Elassoneuria (Ephemeroptera, Oligoneuriidae), Dicentroptilum (Ephemeroptera, Baetidae), Aethaloptera (Trichoptera, Hydropsychidae), Pseudagrion (Odonata, Coenagrionidae) and Tholymis (Odonata, Libellulidae) were exclusively restricted to intermittent sites. Clear differences were observed between sand, gravel, cobble and vegetation habitats. Vegetation and cobbles supported distinct communities, with some taxa exclusively restricted either to vegetation (e.g. Pseudagrion, Leptocerina (Trichoptera, Leptoceridae), Cloeon (Ephemeroptera, Baetidae), Afronurus (Ephemeroptera, Heptageniidae) and Povilla (Ephemeroptera, Polymitarcidae) or cobble (e.g. Aethaloptera and Dicentroptilum) habitats. In terms of ensuring optimum diversity within the subcatchment, we consider conservation of critical habitats (cobbles and vegetation) and maintenance of natural flows as the appropriate management actions.

1. Native freshwater fish populations throughout South Africa's Cape Fold Ecoregion (CFE) are in decline as a result of human impacts on aquatic habitats, including the introduction of nonnative freshwater fishes. Climate change may be further accelerating declines of many species, although this has not yet been studied in the CFE. This situation presents a major conservation challenge that requires assigning management priorities through assessing species in terms of their vulnerability to climate change.2. One factor hindering reliable vulnerability assessments and the concurrent development of effective conservation strategies is limited knowledge of the biology and population status of many species. This paper reports on a study employing a rapid assessment method used in the USA, designed to capitalize on available expert knowledge to supplement existing empirical data, to determine the relative vulnerabilities of different species to climate change and other human impacts. Eight local freshwater fish experts conducted vulnerability assessments on 20 native and 17 non-native freshwater fish species present in the CFE.3. Results show (1) that native species were generally classified as being more vulnerable to extinction than were non-native species, (2) that the climate change impacts are expected to increase the vulnerability of most native, and some non-native, species, (3) that vulnerability hotspots requiring urgent conservation attention occur in the Olifants-Doring, upper Berg and upper Breede River catchments in the south west of the region, (4) that in addition to providing guidance for prioritizing management interventions, this study highlights the need for reliable data on the biology and distribution of many CFE freshwater fishes, and (5) that identification of priority areas for protection should be based on multiple sources of data.

Pseudobarbus verloreni, a new species, is described from material collected in the Verlorenvlei River system on the west coast of South Africa. It differs from its congeners (except Pseudobarbus skeltoni, Pseudobarbus burchelli, and Pseudobarbus burgi) by the presence of two pairs of oral barbels. Pseudobarbus verloreni sp. n. can be distinguished from the three currently described double barbeled Pseudobarbus species by the following combination of characters: pigment pattern, generally deeper body relative to standard length, a longer intestine associated with the deeper body form, shorter snout relative to head length, and much shorter anterior barbels relative to head length. The new species is distinguished from Pseudobarbus burgi in the neighbouring Berg River system by its longer head and longer pre-dorsal length. It seems as if Pseudobarbus verloreni sp. n. has been extirpated from the Langvlei River system and face several threats to its survival in the Verlorenvlei River system.