Paul H. Skelton

Phylogeny and biogeography of the genus Pseudobarbus (Cyprinidae): Shedding light on the drainage history of rivers associated with the Cape Floristic Region

Relationships among the historically isolated lineages of Pseudobarbus were reconstructed using molecular and morphological data. Contradictions between the molecular and morphological phylogenies suggest convergent evolution and homoplasy in some morphological characters. The earliest divergence in Pseudobarbus was between P. quathlambae in Lesotho and the rest of the genus associated with the Cape Foristic Region in South Africa. A close relationship between P. phlegethon from the Olifants River system on the west coast of South Africa and a lineage of P. afer from small river systems in Afrotemperate Forests on the south coast, can only be explained through previous occurrence and subsequent extinction of ancestral populations in the Gourits River system. Several river systems had confluences before reaching lower sea levels, most notably during the last glacial maximum about 18,000 years ago, explaining closely related populations across different river systems. Mainly river capture explains shared lineages across river systems that did not share a common confluence during lower sea levels.

Allopatric differentiation in the Marcusenius macrolepidotus species complex in southern and eastern Africa: the resurrection of M. pongolensis and M. angolensis, and the description of two new species (Mormyridae, Teleostei)

We critically compared local populations of the bulldog fish, Marcusenius macrolepidotus (Peters 1852), from different watersheds, from the furthest south (28° South, South Africa) to the Equator in Kenya. We ascertained allopatric differentiation from topotypical M. macrolepidotus from the Lower Zambezi River (Mozambique) in morphology, electric organ discharges, and molecular genetics for: (1) samples from the Okavango and Upper Zambezi Systems (Botswana and Namibia), (2) samples from South Africas rivers draining into the Indian Ocean, and (3) samples from the East African Tana River (Kenya). Significant genetic distances in the mitochondrial cytochrome b gene and differing ISSR‐PCR profiles corroborate differentiation between the four taxa. We resurrect M. pongolensis (Fowler, 1934) for South Africa (sample 2), and M. angolensis (Boulenger, 1905) for the Quanza River/Angola. We recognize M. altisambesi sp. n. for the Upper Zambezi/Okavango specimens (sample 1), and M. devosi sp. n. for those from Kenya (sample 3).

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.

A critical revision of the churchill snoutfish, genus Petrocephalus Marcusen, 1854 (Actinopterygii: Teleostei: Mormyridae), from southern and eastern Africa, with the recognition of Petrocephalus tanensis, and the description of five new species

We morphologically and genetically studied the southern African electric fish Petrocephalus catostoma, or churchill, and its six nominal species, five of which by synonymization (three valid subspecies). We reinstate the synonymized species, and recognize Petrocephalus tanensis (Whitehead and Greenwood, 1959) from the Tana River in Kenya, also using electric organ discharges. The Okavango delta (Botswana) is inhabited by Petrocephalus okavangensis sp. nov. and Petrocephalus magnitrunci sp. nov., and the Namibian Cunene River by Petrocephalus magnoculis sp. nov. We recognize Petrocephalus petersi sp. nov. for the Lower Zambezi River (Mozambique), and Petrocephalus longicapitis sp. nov. for the Upper Zambezi River (Namibia). The Lufubu River in Northern Zambia is inhabited by Petrocephalus longianalis sp. nov. For the southern churchill, Petrocephalus wesselsi Kramer and Van der Bank, 2000, we confirm intraspecific and interspecific differentiation. Sequence data from mitochondrial DNA confirm differentiation of two new western and two eastern species, forming mutual sister groups.

Changes to the scientific and common names of southern African freshwater fishes

Additions and changes to the scientific and common names of southern African freshwater fishes made since 1993, are recorded and explained. Nineteen new scientific names are listed including five new species, three genus-name changes, three species-name changes and four new records from the area. Recommended common names for nineteen species are listed.

Name changes and additions to the southern African freshwater fish fauna

Changes made to the scientific names of southern African freshwater fishes since 2001 are explained and discussed. Adjustments to the phylogeny and classification of the fauna are outlined. Recent systematic studies on cyprinines are discussed and changes to the genera Labeobarbus (expanded concept), Pseudobarbus (expanded concept), and Enteromius are supported. The introduction of the family names Alestidae and Nothobranchiidae is discussed. Adjustments made to the genera Nannocharax, Micropanchax, Tilapia, Coptodon and Mastacembelus are explained. Species name changes for Hepsetus and Zaireichthys are detailed. New species described from the region, or resurrected from synonymy, since 2001 are listed.

Conservation biology and management of a critically endangered cyprinid, the Twee River redfin, Barbus erubescens (Teleostei: Cyprinidae), of the Cape Floristic Region, South Africa

The Twee River redfin Barbus erubescens is a critically endangered small cyprinid endemic to the Twee River System, a subcatchment of the Olifants-Doring River System of South Africa. It is currently the most threatened freshwater fish in both the Cape Floristic Region and South Africa. It inhabits deep pools in perennial rivers that have an abundance of instream and marginal vegetation and rock cover. Key threats include four introduced invasive fish species and habitat degradation due to increasing intensive agriculture in the Twee River catchment. Unless appropriate management action is taken, it may become the first freshwater fish species in South Africa to become extinct. The purchase of key riparian properties, the eradication of invasive species from part of the river system, the promotion of land-owner awareness, and the establishment of a conservancy as part of a longterm recovery programme are recommended to conserve B. erubescens effectively.

A new species of redfin (Teleostei, Cyprinidae, Pseudobarbus) from the Verlorenvlei River system, South Africa

Abstract 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.

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

Abstract 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 Pseudobarbus 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 Pseudobarbus phlegethon from the Olifants River system on the west coast of South Africa, suggesting that it does not belong to Pseudobarbus afer s.l. Herein we focus on the three lineages within the Pseudobarbus afer s.l. complex and provide new diagnosis for Pseudobarbus afer s.s (Mandela lineage), revalidate Pseudobarbus senticeps (Krom lineage) as a distinct species, and describe a new species Pseudobarbus 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 Pseudobarbus afer and Pseudobarbus 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 Pseudobarbus senticeps from Pseudobarbus 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 Pseudobarbus swartzi sp. n. by possession of fewer scale rows along the lateral line (29–35, mode 32 vs 34–37, mode 36 in Pseudobarbus swartzi), fewer scales around the caudal peduncle (12–16, mode 12 vs 13–17, mode 16 in Pseudobarbus swartzi) and a distinct mesh or net-like pigmentation pattern on latero-ventral scales.

First record of sound production by a South African minnow, Pseudobarbus burchelli (Teleostei: Cyprinidae), the Breede River redfin

The production of sound has been documented for several cyprinid fish species (Stout 1975, Johnston and Johnson 2000, Johnston and Vives 2003). However, no record exists of sound production by any African cyprinid, of which there are currently at least 475 species recognised (Skelton 2001). The production of sound by fishes is frequently associated with breeding behaviours such as courtship displays (Johnston and Vives 2003, Amorim and Almada 2005) and territorial defence (Torricelli and Romani 1986) or when threatened by a potential predator (Fine et al. 1997). This report documents sound production by Pseudobarbus burchelli (Smith 1841), an endangered redfin minnow restricted to the Breede River and associated catchments in the central Cape Floristic Region (CFR), South Africa. There are currently seven recognised species of Pseudobarbus (Skelton 2001) (although new species have recently been reported (Swartz et al. 2007)) with three unique lineages identified within the P. burchelli complex (Swartz 2005). The lineage of the population that is the subject of the current report is from the Breede, Duiwenhoeks and Goukou Rivers. Most species in the genus are restricted to single river catchments and are threatened with extinction due to human activities and from competition or direct predation from invasive fishes. Characteristics of the genus include small size (maximum for P. burchelli = 140 mm SL) and, in breeding males, tubercules on the head, red fins and contrasting patterning (Skelton 1988). Most species in the genus, including P. burchelli, are gregarious, feeding diurnally and, to a lesser degree nocturnally, in schools in open water and exhibit predator-naive behaviour. All of these factors have contributed to the depletion of Pseudobarbus species by alien invasive fishes such as bass (Micropterus spp.) and trout (Salmo trutta and Oncorhynchus mykiss). Sounds were recorded using a mini-disc recorder (Sony MZ-NH1) with a rubber prophylactic covering the microphone, which was mounted on the end of a stick. Because the recorder was uncalibrated, the frequency (Hz) of the sound as shown in Figure 1 may be slightly different from its actual frequency. On each of three occasions when sound was recorded, only one type of sound was heard: bursts of rapid chirps, at rates of up to 150 per minute, which lasted for periods of up to one minute, with short rests of a few seconds between bursts. There were no detectable differences in the frequency of the sounds (chirps per minute) or in the duration of each sound within individuals (Friedman ANOVA) or between individuals (Kruskal-Wallis ANOVA). A sonograph and waveform graph of a representative sound sequence are presented in Figure 1 (Raven Lite version 1.0 programme, Cornell Lab of Ornithology). The volume, pitch and frequency of the chirps increased slightly as the fish were approached, either by the observer or by the stick-mounted recording device. The characteristics of sounds produced by five individual fish recorded in October 2007 are provided in Table 1. In association with each chirp produced, the individual fish flexed into a shallow ‘comma’ shape and then extended the body, simultaneously eliciting sound in a seemingly aggressive display. Only males in breeding condition, with red fins, rostral tubercules, and darker spots along the mid-line of the body, were noted eliciting sounds and displaying the associated behaviour. The size range of individuals that produced sound was estimated to be between 60 and 100 mm, and these individuals appeared to be guarding rock crevices or interstices between cobbles, from which they emerged to display and from which they were very reluctant to move. In some instances the individuals remained hidden or partially hidden within the crevasses whilst producing sound. These ‘territories’ were as close as 2 m apart and were located in water 25–60 cm deep and flowing at 0.2–0.4 m s–1. Sounds were not heard in pools or faster riffle sections. When first noticed in September 2006, whilst snorkelling as part of an ecological study, more than 10 individuals in a 40 m reach, averaging 7 m wide, were noted producing sound and the associated behaviour. In November 2006 we returned to this site with sound-recording equipment, although only one individual then produced sound for a brief moment and this was not recorded. Again, in March 2007, no sounds were heard or recorded, despite the high abundance of actively-feeding fish and males with visible breeding characteristics. Short note