12 research outputs found

    The Victoria Falls, a species boundary for the Zambezi Parrotfish, Cyphomyrus discorhynchus (Peters, 1852), and the resurrection of Cyphomyrus cubangoensis (Pellegrin, 1936) (Mormyridae: Teleostei)

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    Cyphomyrus discorhynchus occurs in the Zambezi River and in the linked systems of the Kwando and the Okavango. We collected specimens from both above and below the Victoria Falls and recorded Electric Organ Discharges. We found a marked degree of anatomical differentiation among the specimens from the Zambezi delta to the Victoria Falls that represents a subspecific, geographical cline, reflecting the great length (1400 km) and high ecological diversity of that river section (Lower and Middle Zambezi). We confirm that the populations above the Falls (i.e. Upper Zambezi, Kwando and Okavango) are differentiated from those below, possessing fewer dorsal fin rays (a median of 30–31 rather than 33–34). The waveforms of the electric organ discharge pulses have four phases and show geographic variation but were briefer for specimens from below the Falls. We resurrect Cyphomyrus cubangoensis (Pellegrin, 1936) for the Upper Zambezi/Kwando/Okavango system

    Report of the multidisciplinary investigation of differentiation and potential hybridisation between two Yellowfish species Labeobarbus Kimberleyensis and L. Aeneus from the Orange-Vaal system

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    From the executive summary]: The relationships within and between two yellowfish species, Labeobarbus aeneus (smallmouth yellowfish) and L. kimberleyensis (largemouth yellowfish) from the Orange-Vaal system were investigated through three independently conducted studies of the same material collected from the Sak River (the type locality of L. aeneus), the upper Orange River at Aliwal North and the lower Orange River at Pella and Onseepkans

    Social Costs of Energy Disruptions

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    Phylogenetic Relationships Between Eight African Species of Mormyriform Fish ('l'eleostei, Osteichthyes): Resolution of a Cryptic Species, and Reinstatement of Cyphomyrus Myers, 1960

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    Phylogenetic relationships between seven elephantfish species from five genera (Mormyridae) that are endemic to southern Africa, and the Nile knifefish of the sister family, Gymnarchidae, were determined using biochemical genetic data, behaviour (the waveforms of the electric organ discharge), morphology, and habitat and food preferences. The results confirmed the existence of an undescribed species of Hippopotamyrus, and that H. ansorgii and H. discorhynchus are not congeners. These distinctions had been suggested by differences in electric organ discharge waveforms and are here substantiated by morphological and genetic data. We recommend the reinstatement of Cyphomyrus discorhynchus (Peters, 1852). Genetic distance (D, Nei, 1972) values suggest confamilial genera (D average of 1.09 for all species studied, and 0.715 for southern African species), with the exception of the sympatric and congeneric species: H. ansorgii and H. sp. (D=0.423). Phylogenies based on morphological and electrophoretic data are congruent

    DNA barcoding of southern African crustaceans reveals a mix of invasive species and potential cryptic diversity.

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    Globally, crustaceans represent one of the most taxonomically diverse and economically important invertebrate group. Notwithstanding, the diversity within this group is poorly known because most crustaceans are often associated with varied habits, forms, sizes and habitats; making species identification by conventional methods extremely challenging. In addition, progress towards understanding the diversity within this group especially in southern Africa has been severely hampered by the declining number of trained taxonomists, the presence of invasive alien species, over exploitation, etc. However, the advent of molecular techniques such as "DNA barcoding and Metabarcoding" can accelerate species identification and the discovery of new species. To contribute to the growing body of knowledge on crustacean diversity, we collected data from five southern African countries and used a DNA barcoding approach to build the first DNA barcode reference library for southern African crustaceans. We tested the reliability of this DNA barcode reference library to facilitate species identification using two approaches. We recovered high efficacy of specimen identification/discrimination; supported by both barcode gap and tree-base species identification methods. In addition, we identified alien invasive species and specimens with 'no ID" in our DNA barcode reference library. The later; highlighting specimens requiring (i) further investigation and/or (ii) the potential presence of cryptic diversity or (iii) misidentifications. This unique data set although with some sampling gaps presents many opportunities for exploring the effect and extent of invasive alien species, the role of the pet trade as a pathway for crustacean species introduction into novel environments, sea food authentication, phylogenetic relationships within the larger crustacean groupings and the discovery of new species

    Global Spore Sampling Project: A global, standardized dataset of airborne fungal DNA

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    Novel methods for sampling and characterizing biodiversity hold great promise for re-evaluating patterns of life across the planet. The sampling of airborne spores with a cyclone sampler, and the sequencing of their DNA, have been suggested as an efficient and well-calibrated tool for surveying fungal diversity across various environments. Here we present data originating from the Global Spore Sampling Project, comprising 2,768 samples collected during two years at 47 outdoor locations across the world. Each sample represents fungal DNA extracted from 24 m3 of air. We applied a conservative bioinformatics pipeline that filtered out sequences that did not show strong evidence of representing a fungal species. The pipeline yielded 27,954 species-level operational taxonomic units (OTUs). Each OTU is accompanied by a probabilistic taxonomic classification, validated through comparison with expert evaluations. To examine the potential of the data for ecological analyses, we partitioned the variation in species distributions into spatial and seasonal components, showing a strong effect of the annual mean temperature on community composition
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