Pseudobarbus outeniqua, Zarei & Bragança & Skelton & Chakona, 2025

Zarei, Fatah, Bragança, Pedro H. N., Skelton, Paul H. & Chakona, Albert, 2025, Pseudobarbus outeniqua sp. nov., a new redfin species (Teleostei, Cyprinidae) from the Cape Fold Ecoregion of South Africa, ZooKeys 1239, pp. 231-255 : 231-255

Pseudobarbus outeniqua sp. nov.

Figs 3 , 4

Barbus asper : Barnard (1943); Jubb (1965, 1967).

Pseudobarbus afer : Skelton (1988).

Pseudobarbus sp. ‘ afer Forest’: Swartz et al. (2007, 2009); Skelton (2024).

Proposed common names.

Forest redfin (English), Wildernis rooivlerkie (Afrikaans).

Type material.

Holotype. • SAIAB 237307 (tag number FZ 03), male, 67.6 mm SL, Kouma River at Willem’s Farm , Klein Brak River system, South Africa, -33.95261111, 21.97691667, collected by A. Chakona, N. Mazungula and X. Mathebula, 25 February 2024 . Hologenetype: • SAIAB SB 11793 , GenBank number: PQ 653965. Paratypes (n = 14). • SAIAB 246084 (tag numbers FZ 01 – FZ 02, FZ 04, FZ 06 – FZ 07, FZ 10 – FZ 11, FZ 13 – FZ 15), 10 unsexed, 46.6–83.2 mm SL, same locality information and collectors as holotype . • BMNH 2024.11.26.1-2 (tag numbers FZ 09 & FZ 12), 2 unsexed, 67.2–80.3 mm SL, same locality information and collectors as holotype . • AMNH 281979 (tag numbers FZ 05 & FZ 08), 2 unsexed, 77.3–80.4 mm SL, same locality information and collectors as holotype . Paragenetypes: SAIAB SB 11791 – SB 11792, SB 11794, 3 specimens, GenBank number: PQ 653963 – PQ 653964, PQ 653966.

Additional non-type materials

(n = 29). • SAIAB 246101 , 17 unsexed, 29.1–57.8 mm SL, Touws River , South Africa, -33.94672778, 22.61263611, collected by A. Chakona, P. H. Skelton and P. Bragança, 21 February 2023 . • SAIAB 128708 , 5 unsexed, 50.1–67.4 mm SL, Causeway at Kruisvallei / George, Keurbooms, South Africa, -33.812, 23.17472, collected by J. Olivier and S. Thorne, 01 March 1983 . • SAIAB 200541 , 2 unsexed, 74.9–86.9 mm SL, Kwaai River , Keurbooms, South Africa, - 33.82, 23.17972, collected by E. Swartz, 11 April 2000 . • SAIAB 128186 , 3 unsexed, 48.6–52.6 mm SL, Kaapsedrif , Tsitsikamma, South Africa, - 34.16, 24.4, collected by A. H. Bok and M. King, 12 May 1982 . • SAIAB 64260 , 1 unsexed, 68.0 mm SL, Tsitsikamma National Park , Groot River, South Africa, collected by I. A. Russel, 26 February 2001 . SAIAB 122981 , 1 unsexed, 47.7 mm SL, Palmietvlei road at Kaapsedrif , Tsitsikamma, South Africa, -34.05, 24.4, collected by D. Heard, 28 October 1976 .

Diagnosis.

Pseudobarbus outeniqua sp. nov. is diagnosed among all currently recognised congeners by the following combination of character states: mouth with one pair of barbels; barbel length 1.0–1.9 times orbit diameter, reaching vertical through posterior edge of eye; pigmentation distinct, with scale centres darkly pigmented, giving the fish an overall speckled appearance, speckling less conspicuous or absent ventrally; presence of a distinct dark mid-lateral band, with a broader anterior half and a narrower posterior half which ends in form of a large triangular mark at the base of the caudal fin; lack of dark spots, dashes, stripes or wavy lines on back and mid-dorsal; scales moderate sized, 35–37 in lateral line series, 14–15 (mode 15) around caudal peduncle, and 16–17 (mode 16) on predorsal region. Detailed comparison of the new species with the other congeners is presented below.

Description.

All morphometric values in the text are presented as holotype first and paratypes, if different, in parentheses. The following description is based on holotype and paratypes from the Klein Brak River system (westernmost population); data for additional non-type specimens from the Keurbooms (central population) and Tsitsikamma (easternmost population) rivers are given in Table 3 .

General morphology. Body proportions and meristics are given in Table 3 . Body moderately elongate, fusiform, with dorsal profile generally more convex than ventral profile, its depth at dorsal fin origin (deepest) 3.6 (3.7–4.2) in SL, body laterally compressed. Caudal peduncle shallow, its depth 0.5 times caudal-peduncle length. Head large, length 3.5 (3.5–3.7) in SL, depressed, depth 5.4 (4.9–5.5) in SL and 0.7 (0.7–0.8) times body depth. Postorbital profile steep. Snout blunt, short, oblique, convex, longer than eye, length 1.6 (1.2–1.8) times eye diameter and 2.7 (2.7–3.1) in head length. Eyes large, diameter 4.4 (3.9–5.0) in head length, and dorsolateral, not extending above dorsal profile, located closer to tip of snout than posterior margin of operculum. Interorbital wide and flat, width 1.5 (1.3–1.7) times eye diameter. Mouth sub-terminal, sickle shaped, its corner reaching vertical through middle of nares. Mouth with a single pair of long maxillary barbels, barbel length 1.3 (1.0–1.9) times orbit diameter, reaching vertical through posterior edge of the eye.

Tuberculation. Mature breeding males with conical tubercles on snout and top of head. Bilateral clusters of large tubercles (2–4 per cluster) present on snout. A row of large tubercles extends in an arc above each naris (3 tubercles) to the antero-dorsal edge of the orbit and then continues posteriorly (3 smaller tubercles) along the dorsal edge of each orbit. Anterior dorsal cluster includes a few small tubercles. Posterior dorsal cluster includes scattered smaller tubercles, progressively become smaller posteriorly. No tubercles were observed on the surface of the fin rays or the free edge of the latero-dorsal scales in the examined specimens.

Scales. LL 35–37 (holotype: 37; paratypes: 35: 6, 36: 3, 37: 5), LD 6, LP 4–5 (holotype: 5; paratypes: 4: 11, 5: 3), LA 4–5 (holotype: 5; paratypes: 4: 3, 5: 11), CP 14–15 (holotype: 15; paratypes: 14: 1, 15: 13), PDS 16–17 (holotype 17; paratypes: 16: 12, 17: 2). Nape naked. Predorsal scales between posterior edge of head and dorsal fin origin embedded and smaller than flank scales. Triangular naked patch between gill cover and anterior base of pectoral fin present; ventral scales between pectoral fin origin and pelvic fin origin reduced and embedded. All scales cycloid.

Fins. Dorsal fin rays iii / 6–7 (holotype iii / 7; paratypes: iii / 6: 1, iii / 7: 13); anal fin rays iii / 5; pectoral fin rays 15–17 (holotype: 16; paratypes: 15: 6, 16: 7; 17: 1); pelvic fin rays 8; caudal fin principal rays 10 + 9. Dorsal fin situated almost in the centre of the body (excluding caudal fin), origin slightly behind vertical through origin of pelvic fin, distal margin straight to slightly concave, tip of depressed dorsal fin almost reaches to vertical through posterior base of anal fin in mature males, reaches within two scales to vertical through posterior base of anal fin. Pectoral fins fan-shaped, larger in males than females, reaches and surpasses base of pelvic fin in males, reaches two scales to base of pelvic fin in females. Pelvic fin origin slightly in front of dorsal fin origin, tip of depressed pelvic fin does not reach anterior origin of anal fin, except in mature males. Anal fin distal margin almost straight to slightly convex, origin closer to anterior base of pelvic fin than caudal fin base. Caudal fin forked.

Osteology. Vertebral column including Weberian apparatus and urostyle: total vertebrae 36–38 (holotype: 37; paratypes: 36: 10, 37: 3, 38: 1), predorsal vertebrae 12–13 (holotype: 12; paratypes: 12: 12, 13: 2), precaudal vertebrae 19–20 (holotype: 20; paratypes: 19: 9, 20: 5), and caudal vertebrae 16–18 (holotype: 17; paratypes: 16: 1, 17: 12, 18: 1).

Colouration (live specimens). Refer to Fig. 3 for general live colouration. Body golden-tan laterally, becoming darker dorsally, and lighter to white ventrally. Scale centres darkly pigmented, giving an overall “ speckled hen ” appearance. Base of fins bright scarlet; caudal fin least affected by this colouration. Distinct dark mid-lateral band, covering three rows of scales, with a broaden anterior half from behind the head to vertical through anal-fin origin and a narrower posterior half to the base of the caudal fin, ends in form of a large triangular mark.

Colouration (preserved). Background colour in alcohol preserved specimens after three months since collection, light brownish grey, becoming darker dorsally and lighter ventrally (Fig. 4 ). Scale centres darkly pigmented. Flanks with distinct dark mid-lateral band. The bright red pigmentation on base of fins first turns orange to yellow, then fades.

Distribution.

Pseudobarbus outeniqua sp. nov. (referred to as the ‘ Forest’ lineage by Swartz et al. 2007) is endemic to the Cape Fold Ecoregion of South Africa where it has a wide distribution range which includes a number of small isolated coastal catchments. The known distribution range extends from the Klein Brak River system in the Western Cape Province to the Tsitsikamma River system which is at the eastern end of the Western Cape Province (Fig. 5 ). There is very little information about the population sizes across this taxon’s distribution range, but ad hoc surveys indicate that the known populations are relatively abundant. The extent of alien fish invasion in the river systems where this taxon occurs is poorly documented. However, a trout farm exists within the Keurboom River catchment and that system has been extensively stocked with both brown and rainbow trout ( Harrison 1966; Impson and Swartz 2011). Tilapia sparrmanii Smith, 1840 was also common in that system during our recent surveys.

Etymology.

The specific epithet outeniqua refers to the Outeniqua mountain range and highlights the species’ occurrence in streams draining its southern slopes within the southern Cape Fold Ecoregion.

Conservation status.

This species is threatened by invasive alien fish species, excessive water abstraction, increased sedimentation from forestry activities and pollution resulting from urban development and expansion. The spatial extent and severity of these impacts require further study. Pseudobarbus outeniqua sp. nov. occurs in isolated mountain tributaries. The species has an extent of occurrence (EOO) of 4035 km 2 and an area of occupancy (AOO) of 168 km 2. It is known from 11 distinct catchments and at least 16 locations [Klein Brak, Kaaimans, Touws (upper Touws and Duiwe River tributaries), Swartvlei (Karatara tributary), Goukamma / Homtini, Knysna (upper Knysna and Gouna tributaries), Keurbooms (upper Keurbooms, Bietou and Palmiet tributaries), Groot, Bloukrans and Tsitsikamma]. Pseudobarbus outeniqua sp. nov. was thus assessed as Near Threatened under criterion B 1 b (iii) + B 2 b (iii) ( Chakona et al. 2022). The taxon is likely to be experiencing ongoing decline in quality of habitat due to water abstraction, agriculture, and urban development as well as impacts from forestry activities that has resulted in sedimentation of some of the streams. Invasive alien fish species likely pose a major threat to the extent of occurrence of this taxon but the degree of invasion and extent of impacts need to be assessed.

Habitat and ecology.

This taxon occurs in dark peat-stained forest streams and prefers cover in a variety of microhabitats, ranging from pools with emergent vegetation (mainly palmiet), to runs and riffles with bed rock, boulders, and cobble substratum (Fig. 6 ). No information is available on the breeding ecology of this taxon, but it is likely to be similar to congeneric species that spawn after an increase in river flow during the rainy season, commencing in October and extending to February ( Cambray 1994). Spawning generally occurs in riffle areas upstream of pools where eggs are deposited under mid-channel boulders. Once hatched, larvae drift from riffles into pool areas where they feed in the pelagic zone ( Cambray 1994). Further research is required to improve our understanding of the ecology and biology of this taxon.

Comparative remarks.

Pseudobarbus outeniqua sp. nov. is easily distinguishable from P. burchelli , P. burgi , P. skeltoni , P. verloreni , and P. vulnerata by possession of a single pair of oral barbels (vs two pairs). The new species is also different form all single-barbeled Pseudobarbus species except P. asper in having an overall “ speckled hen ” colouration pattern.

Pseudobarbus outeniqua sp. nov. differs from P. afer in having longer barbels (22.2–40.0 % HL and 1.0–1.9 times orbit diameter, reaching vertical through posterior edge of eye vs 12.1–27.2 % HL and 0.4–1.1 times orbit diameter, barbels do not surpass the vertical through posterior margin of pupil), more scales in lateral line series (35–38, mode 35–37 vs 29–35, mode 32) and on predorsal region (16–17, mode 16 vs 13–16, mode 15), a mid-lateral band which terminates in a large triangular blotch at the base of the caudal fin (vs lack of a conspicuous blotch of pigment at the base of the caudal fin), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs the Sundays, Swartkops, and Baakens rivers, which discharge into the Algoa Bay; Fig. 5 ).

Pseudobarbus outeniqua sp. nov. further differs from P. asper in having a longer head (27.3–30.7 vs 24.7–28.2 % SL), possession of fewer scales in lateral line series (35–37 vs 35–45, mode 37–40), on predorsal region (16–17, mode 16 vs 18–26, mode 20–23), around the caudal peduncle (14–15, mode 15 vs 16–22, mode 18–20), lateral line to dorsal fin origin (5–6, mode 6 vs 6–9, mode 7–8), lateral line to pelvic fin origin (4–5, mode 4 vs 5–8, mode 5–7), and lateral line to anal fin origin (4–5, mode 5 vs 5–8, mode 5–7), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs main branches of the Gourits and upper and middle reaches of Gamtoos system; Fig. 5 ) (morphological data for P. asper from widespread localities in the Gamtoos and Gourits systems, including 16 toptypic specimens in this study and 110 specimens from Skelton 1988).

Pseudobarbus outeniqua sp. nov. also differs from its closest relative, P. phlegethon , in having a longer head (27.3–28.9 vs 24.4–26.6 % SL), longer barbels (22.2–40.0 % HL and 1.0–1.9 times orbit diameter, reaching vertical through posterior edge of eye vs 2.4–15.3 % HL and 0.1–0.6 times orbit diameter, not reaching vertical through posterior edge of eye), more pectoral fin rays (15–17, mode 15–16 vs 12–15, mode 14), lack of prominent black spots and patches on the body (vs presence), tuberculation of head in mature breeding males (presence of well-developed large to small conical tubercles on the snout and on top of the head vs head tubercles usually absent or poorly developed in some specimens), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs the Olifants-Doring River system on the west coast of South Africa; Fig. 5 ).

Pseudobarbus outeniqua sp. nov. is also easily distinguishable from P. quathlambae and P. kubhekai by having larger and fewer scales, 35–37 scales in lateral line series (vs scales very small, 51–72 scales in lateral line series), longer barbels (1.0–1.9 times orbit diameter, reaching vertical through posterior edge of eye vs less than orbit diameter, not reaching the vertical through the middle of pupil), tuberculation of head in mature breeding males (large to small conical tubercles on the snout and on top of the head vs numerous minute, conical tubercles on the snout, top of the head, operculum, and below the orbit), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs tributaries of the upper Orange River system in the Lesotho Highlands and the Mkhomazi and Mzimkhulu river systems in KwaZulu Natal; Fig. 5 ). It further differs from P. quathlambae by having fewer vertebrae (36–38, mode 36 vs 38–40, mode 39–40) and the absence of dark spots or wavy lines on the back (vs presence of bi-lateral series of discrete predorsal spots, dashes, or vermiculations). Skelton (1988) also showed that P. afer s. l. and P. quathlambae differ in the shape and number of pharyngeal teeth as well as gut length.

Pseudobarbus outeniqua sp. nov. also differs from P. senticeps in having more scales in the lateral line series (35–37 vs 25–30, mode 29), around the caudal peduncle (14–15, mode 15 vs 10–12, mode 12) and on the predorsal region (16–17, mode 16 vs 12–15, mode 15), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs the Krom River system; Fig. 5 ).

Pseudobarbus outeniqua sp. nov. also differs from P. swartzi in having a wider inter-obit (32.0–34.8 % HL and 1.3–1.7 times eye diameter vs 25.7–31.2 % HL and 1.0–1.3 times eye diameter), smaller modes for total vertebrae (36 vs 37), precaudal vertebrae (19 vs 20), caudal vertebrae (17 vs 18), and predorsal vertebrae (12 vs 13), a distinct mid-lateral band which terminates in a triangular blotch at the base of the caudal fin (vs mid-lateral band present but obscure, black blotch at the base of caudal fin inconspicuous), and a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs the Kougaberg, Baviaanskloofberg, and Elandsberg tributaries of the Kouga and Groot sub-catchments of the Gamtoos River system, and the Kabeljous and Swart river systems which discharge into the St Francis Bay; Fig. 5 ).

Pseudobarbus outeniqua sp. nov. also differs from P. tenuis by absence of a dark mid-dorsal stripe (vs presence of a dark mid-dorsal stripe which is sometimes interrupted to form a series of dashes), and having a broad mid-lateral band in front of vertical through anal-fin origin (vs mid-lateral band progressively becomes narrower anteriorly). Pseudobarbus outeniqua sp. nov. is deeper bodied than P. tenuis and differs in pharyngeal teeth and gut length characteristics ( Skelton 1988). It has a different distributional range (coastal rivers of the Outeniqua and Tsitsikamma mountain ranges from Klein Brak east to Tsitsikamma vs main branches of the Gourits, Bitou, and Keurbooms; Fig. 5 ).

Figures

Figure 3. Live specimens of Pseudobarbus outeniqua sp. nov. from the Klein Brak River system A SAIAB 237307 (tag number FZ 03), male, holotype, 67.6 mm SL B SAIAB 246084 (tag number FZ 04), paratype, 80.6 mm SL C SAIAB 246084 (tag number FZ 06), paratype, 77.9 mm SL.

Figure 4. Preserved specimens of Pseudobarbus outeniqua sp. nov. from the Klein Brak River system A SAIAB 237307 (tag number FZ 03), male, holotype, 67.6 mm SL B SAIAB 246084 (tag number FZ 04), paratype, 80.6 mm SL C SAIAB 246084 (tag number FZ 02), paratype, 83.2 mm SL.

Figure 5. Distribution map of all single-barbeled Pseudobarbus species based on the SAIAB fish collection. The type locality of Pseudobarbus outeniqua sp. nov. at the Klein Brak River system is marked with a square.

Figure 6. Habitat of Pseudobarbus outeniqua sp. nov., Kouma River at Willem’s Farm, Klein Brak River system.