Pseudobarbus burchelli ( Smith, 1841 )

Zarei, Fatah, Martin, Melissa B., Skelton, Paul H. & Chakona, Albert, 2025, Systematic review of Pseudobarbus burchelli (Teleostei, Cyprinidae), with revalidation of P. vulneratus and description of a new species, Zoosystematics and Evolution 101 (3), pp. 1271-1296 : 1271-1296

Pseudobarbus burchelli ( Smith, 1841)

English name: Tradouw redfin / Barrydale redfin Afrikaans name: Tradouw-rooivlekie / Barrydale-rooivlekie Figs 4 , 5

Barbus (Pseudobarbus) burchelli Smith, 1841 : no pagination, p 1 XI, no. 1 (Tradouw River, Breede River system, southwestern Cape Province, South Africa, -33.947222, 20.710833).

Pseudobarbus burchelli – Skelton 1988: 264; Skelton 2024: 245.

Neotype.

• SAIAB 126387 ( AMG / P 7223 ), 102 mm SL, Tradouw River , Breede River system, South Africa, -33.9472, 20.71083, collected by S. Thorne, 13 December 1978. Neotype designated by Skelton (1988).

Additional material

(n = 28). • SAIAB 200882 (tag numbers X 2 – X 10), 9 specimens, 68.6–91.7 mm SL, Tradouw River , Breede River system, South Africa, -33.9358, 20.7094, collected by A. Chakona & E. Swartz, 16 February 2009 . • SAIAB 200876 (tag numbers M 1 – M 6), 6 specimens, 63.9–98.4 mm SL, Tradouw River , Breede River system, South Africa, -33.9567, 20.7078, collected by A. Chakona & E. Swartz, 15 February 2009 . • SAIAB 200877 (tag numbers M 7 – M 10), 4 specimens, 56.8–83.9 mm SL, Tradouw River , Breede River system, South Africa, -33.91575, 20.7464, collected by A. Chakona & E. Swartz, 15 February 2009 . • SAIAB 200880 , 4 specimens, 72.5–84.6 mm SL, Moeras , Tradouw River, Breede River system, South Africa, -33.9212, 20.752972, collected by A. Chakona & E. Swartz, 15 February 2009 ; • SAIAB 235751 , 5 specimens, 78.2–106.8 mm SL, Huis River , Breede River system, South Africa, -33.92225, 20.75361, collected by A. Chakona, P. Bragança, P. H. Skelton & M. Jordaan, 12 April 2022 .

Diagnosis.

Pseudobarbus burchelli is diagnosed among all currently recognised congeners by the following combination of character states: mouth subterminal, with two pairs of barbels; head length 25.7–28.8 % SL; interorbital width 32.7–37.5 % HL; anterior barbel length 9.4–26.4 % HL; orbit diameter 18.5–24.2 % HL; head width (at operculum 62.4–71.5 % HL, at eye 49.3–53.9 % HL, at mouth corner 37.4–43.6 % HL); lateral-line scale count 35–38, usually 35–37; circumpeduncular scale count 14–16, usually 15–16; absence of linear stripes; presence of dorsal spots and mid-lateral blotches on the body; tuberculation of head in mature breeding males: large to small conical / blunt tubercles, 3–10 in each snout cluster, single row above each naris with 2–5 tubercles per cluster, and single row above each orbit with 2–6 tubercles per cluster; and 2–3, usually 2 teeth in the outer pharyngeal tooth row. Additionally, Pseudobarbus burchelli is the only redfin species found in the Huis and Tradouw catchments of the Breede River system.

Description.

All morphometric values in the text are presented as neotype first and additional material, if different, in parentheses.

General morphology. Body proportions and meristic data are provided in Table 3 . Body moderately elongated, fusiform; dorsal profile more convex than ventral; max body depth in front of dorsal fin 3.5 (3.6–4.4) in SL; laterally compressed. Caudal peduncle shallow, depth 0.5 (0.5–0.6) times caudal-peduncle length. Head large, length 3.5 (3.5–3.9) in SL, depressed, depth at eye 6.4 (6.1–7.1) in SL and 0.5 (0.5–0.7) times maximum body depth. Postorbital profile steep. Snout blunt, short, oblique, convex; longer than eye, length 2.0 (1.4–1.9) times eye diameter and 2.7 (2.7–3.1) in head length. Eyes large; diameter 5.4 (4.1–5.1) in head length; dorsolateral, not above dorsal profile, closer to tip of snout than posterior margin of operculum. Interorbital broad and flat, 1.9 (1.4–1.8) times eye diameter. Mouth sub-terminal, sickle-shaped; corner reaches vertical line through middle of nares. Mouth has two pairs of prominent barbels. Anterior barbel length variable, length 1.3 (0.5–1.2) times orbit diameter, ranging from significantly short of anterior eye margin to extending to the midpoint of the eye. Posterior barbel length variable, 2.5 (0.7–2.2) times orbit diameter, ends between mid-point of eye and slightly beyond preopercular margin.

Tuberculation. Mature breeding males display conical tubercles (neotype) or typically blunt tubercles of varying sizes on the snout and top of the head. Bilateral clusters of large tubercles, ranging from 3 to 10 per cluster, present on the snout (Fig. 6 ). An arc of tubercles, varying from large to small and resembling snout tubercles, extends above each naris (2–5 per cluster) to the antero-dorsal edge of the orbit. This continues posteriorly with a single row of 2–6 tubercles along the dorsal edge of each orbit, larger in the front. The anterior dorsal cluster features several small or tiny tubercles, while the posterior dorsal cluster contains scattered minute tubercles that gradually decrease in size towards the back. In the neotype, a row of minute tubercles is found along the free edge of all body scales, with the exception of the ventral scales located anterior to the pelvic origin. The dorsal and pectoral fin rays of the neotype display 1–2 lines of minute tubercles. In contrast, the other examined specimens showed no tubercles on the fin rays or the free edges of their body scales.

Scales. LL 35–38 (neotype: 37; other material: 35: 4, 36: 9, 37: 5, 38: 1), LD 5–7 (neotype: 6; other material: 5: 1, 6: 16, 7: 2), LP 4–5 (neotype: 5; other material: 4: 1, 5: 18), LA 4–5 (neotype: 5; other material: 4: 4, 5: 15), CP 14–16 (neotype: 14; other material: 14: 2, 15: 5, 16: 10), PDS 14–18 (neotype: 15; other material: 14: 1, 15: 6, 16: 5, 17: 5, 18: 2). The predorsal scales, located between the back edge of the head and the start of the dorsal fin, are smaller and embedded compared to the scales on the flanks. The ventral scales between the origins of the pectoral and pelvic fins are reduced and embedded. All scales cycloid.

Fins. Dorsal fin rays iv / 7; anal fin rays iv / 5 – iv / 6 (neotype: iv / 5; other material: iv / 5: 17, iv / 6: 2); pectoral fin rays 13–16 (neotype: 14; other materials: 13: 5, 14: 9, 15: 4, 16: 1); pelvic fin rays 8; caudal fin branched rays 17. The dorsal fin is positioned nearly in the centre of the body (not counting the caudal fin), with its origin just behind the vertical line that runs through the pelvic fin’s origin; the distal edge is straight or slightly concave, and the tip of the lowered dorsal fin is 1–3 scales short of the vertical line at the rear base of the anal fin. The pectoral fin exhibits a fan-like morphology and shows variability in length, either reaching or exceeding the origin of the pelvic fins in both sexes or being 1–4 scales shorter. The origin of the pelvic fin is positioned slightly anterior to the origin of the dorsal fin; their length is variable, with the tip of the lowered pelvic fin either reaching or falling 1–3 scales short of the anterior origin of the anal fin in both sexes. The distal margin of the anal fin is nearly straight to slightly convex, with its origin located closer to the anterior base of the pelvic fin than to the base of the caudal fin. The caudal fin is forked.

Osteology (n = 5). Vertebral column including Weberian apparatus and urostyle: total vertebrae 36, predorsal vertebrae 11–12 (neotype: 12; other material: 11: 1, 12: 3), precaudal vertebrae 19–20 (neotype: 20; other material: 19: 2, 20: 2), caudal vertebrae 16–17 (neotype: 16; other material: 16: 2, 17: 2).

Gill rakers (n = 5). 2–4 + 1 + 7 – 12 (epibranchial: 2: 1, 4: 4; angle: 1: 5; ceratobranchial: 7: 1, 11: 3, 12: 1).

Pharyngeal teeth (n = 5). Three rows of pharyngeal teeth, teeth pattern 2–3, 2–3, 4–5 + 4–5, 2–3, 2. The distribution frequency of pharyngeal teeth is given in Table 4 .

Colour of live specimens.

Refer to Fig. 5 for live colouration. Dorsal colour dark golden-brown to olive-brown; ventral colour white to yellowish white. Fins with bright scarlet bases, less intense in caudal fin. Mid-lateral band distinct or indistinct; if distinct, typically with large triangular mark at caudal base. Dorsum features dark brown spots and blotches; irregular spots may also occur along posterior body.

Colour of preserved specimens

(Fig. 4 ). The flanks typically display a distinct dark brown mid-lateral band that terminates in a triangular shape just anterior to the base of the caudal fin; this band may be less pronounced or absent in darker individuals and breeding males. The dorsal head and body are dark or dark brown, transitioning to a lighter colour ventrally. Dorsal spots and mid-lateral blotches were absent in the examined specimens.

Distribution and ecology.

Pseudobarbus burchelli has a limited distribution, being confined to the Huis and Tradouw rivers within the Breede River system (Fig. 2 ; Swartz et al. 2009, 2014; Chakona et al. 2013, 2024).

It has been recorded to occur in deep rocky pools and flowing rocky runs ( Skelton 2024).

Conservation.

This lineage is classified as Critically Endangered (CR) in the latest IUCN Red List Assessment for freshwater fishes of South Africa ( Chakona et al. 2022; Skelton 2024). Its restricted population is under threat from introduced smallmouth bass, water abstraction for urban and agricultural use, and deterioration of water quality ( Skelton 2024).

Etymology.

The species is named after William Burchell (1781–1863), a naturalist and early explorer of South Africa ( Skelton 1988).

Figures

Figure 2. Distribution map of all double-barbeled Pseudobarbus species / lineages based on genetic data (this study; Bloomer and Impson 2000; Tsigenopoulos et al. 2002; Chakona et al. 2013, 2014; Swartz et al. 2014).

Figure 4. Pseudobarbus burchelli, SAIAB 126387, male, neotype, 102 mm SL, Tradouw, Breede River system. A. lateral view; B. dorsal view.

Figure 5. Live specimens of Pseudobarbus burchelli (SAIAB 235751) from the Huis River, Breede River system.

Figure 6. A. Diagrammatic representation of the head tubercle pattern in a mature breeding male redfin: a, cluster on snout; b, row above nares; c, row above orbit; d, anterior dorsal cluster; e, posterior dorsal cluster (modified from Skelton 1988). Tuberculation of head in mature breeding males of B. Pseudobarbus burchelli (SAIAB 126387, neotype, 102 mm SL, Tradouw catchment, Breede River system); C. P. skeltoni (SAIAB 187243, holotype, 158.2 mm SL, Riviersonderend River upstream, Breede River system); D. P. vulneratus (SAIAB 210457, 63.6 mm SL, Duiwenhoks River system), and E. P. agulhas sp. nov. (SAIAB 246288, 66.4 mm SL, Klein River system).