Comparative biogeography and ecology of freshwater fishes in the Breede and associated river systems, South Africa

Distribution patterns and levels of genetic diversity in extant taxa are a product of complex palaeogeographic processes and climatic oscillations as well as the species’ intrinsic ecological adaptations. The Cape Floristic Region of South Africa presents a unique system for studying the processes that promote species diversification and distribution patterns. This region has a high degree of endemism of both terrestrial and aquatic biota and is clearly isolated from neighbouring areas by the Cape Fold Mountains and the Great Escarpment. The objective of this study was to firstly examine the ecology of freshwater fishes belonging to the genera Galaxias, Pseudobarbus and Sandelia in the south-western CFR. This was followed by an assessment of the genetic diversity of these taxa. Unique lineages were identified and their distribution was mapped. The work aimed to explore the role of the region’s complex palaeogeographic and climatic history as well as the role of the species’ ecological adaptations in driving lineage diversification and shaping contemporary distribution patterns. The four main components of the study can be summarised as follows: 1. Habitat associations of three widely distributed lineages of Galaxias zebratus Pseudobarbus burchelli and Sandelia capensis were evaluated at multiple localities in minimally disturbed mountain tributaries of the Breede, Duiwenhoks and Goukou River systems. The lineages have distinct habitat associations which were related to differences in their morphological traits. The slender-bodied Galaxias ‘nebula’ and the fusiform-shaped Pseudobarbus ‘Breede’ are capable of exploiting upper reaches with faster water velocity. By contrast, the laterally compressed Sandelia ‘eastern’ is restricted to lower reaches, making this lineage more susceptible to a wide array of impacts. 2. A recently discovered lineage of Galaxias zebratus, (Galaxias ‘nebula’), was found to be capable of tolerating emersion for a prolonged period of time. This is the first time that such capabilities have been documented in an African galaxiid. These adaptations have implications for the interpretation of Galaxias ‘nebula’s wide distribution range. 3. The phylogeography of Galaxias ‘nebula’ across its entire distribution range was investigated using two mitochondrial genes (cytochrome c oxidase subunit I (COI) and cytochrome b (cyt b)). This lineage has a complex evolutionary history that was influenced by both intrinsic and extrinsic factors. Rare events such as episodic drainage connections during Pleistocene and Holocene pluvial periods, possibly augmented by river confluences during periods of lower sea-levels and river capture events seem to be the most credible explanation for the extensive contemporary distribution and the relatively shallow genetic divergence between different river systems. 4. Mitochondrial cyt b sequences were used (i) to assess genetic diversity in G. zebratus, P. burchelli and S. capensis from the south-western CFR and (ii) to determine the roles of intrinsic ecological adaptations and extrinsic landscape and climatic changes in promoting genetic diversification and shaping present day distribution patterns of lineages in the three taxa. Marine incursions during periods of major sea-level transgressions are proposed to have isolated populations in upland refugia, thereby driving allopatric divergence in these species. Subsequent connections of rivers during wetter periods and lower sea-levels are proposed to have facilitated post-speciation dispersal of lineages to attain present day distribution patterns. While detailed morphological studies and further genetic analysis are needed to substantiate the taxonomic status of the newly discovered lineages of Galaxias zebratus, Pseudobarbus burchelli and Sandelia capensis, results of the present study indicate that the south-western CFR represents a previously unrecognised centre of freshwater fish diversity and microendemism in the broader Cape Floristic Region. Accurate identification of lineages and comprehensive mapping of their distribution is a fundamental pre-requisite for ecological studies, assessing conservation status and implementation of appropriate conservation measures

The status and distribution of a newly identified endemic galaxiid in the eastern Cape Fold Ecoregion, of South Africa

DNA-based studies have uncovered cryptic species and lineages within almost all freshwater fishes studied thus far from the Cape Fold Ecoregion (CFE) of South Africa. These studies have changed the way the CFE is viewed, as almost all stream fishes that were previously consid-ered to be of low conservation priority, because they were perceived to have broad geographical ranges, con-tain multiple historically isolated lineages, many of which are narrow-range endemics

The genetic legacy of lower sea levels : does the confluence of rivers during the last glacial maximum explain the contemporary distribution of a primary freshwater fish (Pseudobarbus burchelli, Cyprinidae) across isolated river systems?

The primary freshwater fish Pseudobarbus burchelli (Smith 1841) occurs across four presently isolated river systems in the south-western cape floristic region of South Africa. Mitochondrial DNA cytochrome b (701 base pairs) and control region (601 base pairs) genes were sequenced to assess the evolutionary history of P. burchelli and evaluate the role of climatic and landscape changes in shaping patterns of genetic variation in this species. We identified three historically isolated lineages in P. burchelli: a widespread lineage that occurs across three isolated river systems and two geographically restricted lineages. The results were evaluated against predictions of the confluence of river systems during low sea levels of the last glacial maximum. Occurrence of the widespread Breede lineage in the Duiwenhoks River system is consistent with reconstructed palaeoriver systems. However, the occurrence of this lineage in the Goukou river system that formed part of the eastern Gourits–Goukou palaeoriver system can only be explained by translocation or a recent river capture or episodic inundation of low drainage divides. Extreme ecological gradients or the potential presence of instream physical barriers could have prevented an exchange of lineages between the Breede and Heuningnes river systems.Table Mountain Fund and Prince Bernhard Scholarships, the National Research Foundation (South Africa) and the Claude Leon Foundation.http://link.springer.com/journal/10750hb201

The Macroinvertebrate Communities Of Two Upland Streams In Eastern Zimbabwe With Reference To The Impact Of Forestry

Benthic macroinvertebrates and physico-chemical parameters of the water were examined from two fast flowing streams, the Nyahode River which drains a pine monoculture catchment and the Haruni River which drains an undisturbed deciduous forest catchment in the Chimanimani Mountains, Eastern Zimbabwe. Benthic samples and environmental data were collected in October 2004, December 2004 and January 2005. The water quality was similar in many respects but turbidity was significantly higher (p<0.05) in the Nyahode River compared to the Haruni River (mean 17.1 NTU and 6.0 NTU respectively). Conductivity was almost three times higher in the Nyahode (66 µS cm-1) than the Haruni (24 µS cm-1). The impact of forestry on faunal composition was evident on Ephemeroptera (Euthraulus, Afronurus and Dicercomyzon), Plecoptera (Neoperla spio) and Trichoptera (Macrostemum capense) (EPT) richness. Absence of shredders from both streams is a result of the low retention of Course Particulate Organic Matter (CPOM) in the streams due to the rapid flows whilst dominance of filterers suggests that the retention of organic material seems to be limited to Fine Particulate Organic Matter (FPOM). These results indicate that unless reference conditions are established first, results from biotic indices could be completely misleading because absence of some taxa could not be due to human impact but is just a natural phenomenon. Many of the taxa collected from both rivers were sensitive to water quality change (ASPT, 5.6 to 7.8) indicating good water quality which is attributable to the currently underdeveloped nature of the catchment

A review of the Pseudobarbus afer (Peters, 1864) species complex (Teleostei, Cyprinidae) in the eastern Cape Fold Ecoregion of South Africa

The Eastern Cape redfin, Pseudobarbus afer, has long been considered to be a single widespread and variable species occurring in multiple isolated river systems in the Cape Fold Ecoregion (CFE) at the southern tip of Africa. Mitochondrial cytochrome b and control region sequence data of individuals from populations currently assigned to P. afer across the species’ distribution range revealed existence of four deeply divergent taxonomic units: (i) the Mandela lineage confined to the Sundays, Swartkops and Baakens river systems, (ii) the Krom lineage endemic to the Krom River system, (iii) the St Francis lineage occurring in the Gamtoos and adjacent river systems, and (iv) the Forest lineage occurring in several coastal river systems from the Tsitsikamma to the Klein Brak River system. The Forest lineage is closely related to P. phlegethon from the Olifants River system on the west coast of South Africa, suggesting that it does not belong to P. afer s.l. Herein we focus on the three lineages within the P. afer s.l. complex and provide new diagnosis for P. afer s.s (Mandela lineage), revalidate P. senticeps (Krom lineage) as a distinct species, and describe a new species P. swartzi (St Francis lineage). The three species exhibit subtle differences, which explains why they were previously considered to represent a single variable and widespread species. Pseudobarbus senticeps differs from both P. afer and P. swartzi by having fewer (i.e. larger) scales (25–33, mode 29 lateral line scale series; 10–12, mode 11 circumpeduncular scales) and presence of a lateral stripe which terminates in a conspicuous triangular blotch at the base of the caudal fin. Long barbels which reach or surpass the vertical through the posterior edge of the eye further separate P. senticeps from P. afer s.s. which possesses simple short barbels which do not reach the vertical through the posterior margin of the eye. Pseudobarbus afer s.s differs from P. swartzi sp. n. by possession of fewer scale rows along the lateral line (29–35, mode 32 vs 34–37, mode 36 in P. swartzi), fewer scales around the caudal peduncle (12–16, mode 12 vs 13–17, mode 16 in P. swartzi) and a distinct mesh or net-like pigmentation pattern on latero-ventral scales

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

Enteromius pallidus was described by Smith in 1841 without a designated type specimen for the species. Herein, we designate a specimen from the Baakens River system as a neotype for E. pallidus and provide a thorough description for this species to facilitate ongoing taxonomic revisions of southern African Enteromius. Enteromius pallidus can be distinguished from the other minnows in the “goldie barb group” by having an incomplete lateral line, lack of distinct chevron or tubular markings around lateral line pores, absence of a distinct lateral stripe, absence of wavy parallel lines along scale rows and lack of black pigmentation around the borders of the scales. We provide mtDNA COI sequences for the neotype and an additional specimen from the Baakens River as DNA barcodes of types and topotypes are a fundamental requirement for further taxonomic studies

FIGURE 1 in A new redfin species, Pseudobarbus skeltoni (Cyprinidae, Teleostei), from the Cape Floristic Region, South Africa

FIGURE 1. Bayesian phylogram with Bayesian posterior probabilities, showing the genetic distance between Pseudobarbus skeltoni sp. nov. compared to all other Pseudobarbus lineages. Although phylogenetic relationships among Pseudobarbus lineages should be based on Swartz et al. (2009) due to more data that were analysed, it is clear from the present study that P. skeltoni is closely related to Pseudobarbus lineages that have two distinct pairs of barbels. More genes will have to be analysed to resolve the phylogenetic relationships within this group.Published as part of &lt;i&gt;Chakona, Albert &amp; Swartz, Ernst R., 2013, A new redfin species, Pseudobarbus skeltoni (Cyprinidae, Teleostei), from the Cape Floristic Region, South Africa, pp. 565-577 in Zootaxa 3686 (5)&lt;/i&gt; on page 568, DOI: 10.11646/zootaxa.3686.5.5, &lt;a href="http://zenodo.org/record/10098673"&gt;http://zenodo.org/record/10098673&lt;/a&gt

FIGURE 7 in A new redfin species, Pseudobarbus skeltoni (Cyprinidae, Teleostei), from the Cape Floristic Region, South Africa

FIGURE 7. Pictures showing localities and habitat where specimens of Pseudobarbus skeltoni were collected: (A) upper Riviersonderend (note the foot bridge of hiking trail crossing the river just below the gauging weir), and (B) Krom River.Published as part of &lt;i&gt;Chakona, Albert &amp; Swartz, Ernst R., 2013, A new redfin species, Pseudobarbus skeltoni (Cyprinidae, Teleostei), from the Cape Floristic Region, South Africa, pp. 565-577 in Zootaxa 3686 (5)&lt;/i&gt; on page 575, DOI: 10.11646/zootaxa.3686.5.5, &lt;a href="http://zenodo.org/record/10098673"&gt;http://zenodo.org/record/10098673&lt;/a&gt