Pseudobarbus swartzi Chakona & Skelton, 2017
Gamtoos redfin
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Family:  Cyprinidae (Minnows or carps), subfamily: Smiliogastrinae
Max. size:  8.11 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater,
Distribution:  Africa: Gamtoos, Kabeljous and Swart River systems in South Africa (Ref. 114782).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 10-11; Anal spines: 0-0; Anal soft rays: 8-8; Vertebrae: 37-38. Diagnosis: The possession of a single pair of oral barbels separates Pseudobarbus swartzi from P. burchelli, P. burgi, P. skeltoni and P. verloreni, all with two pairs (Ref. 114782). It differs from P. quathlambae by having larger scales and fewer scale rows along the lateral line , 35-37 lateral line scales in P. swartzi vs. more than 65 scales along lateral line in P. quathlambae (Ref. 114782). Pseudobarbus swartzi and P. senticeps show some overlap in barbel length, but are clearly separated by scale size; Pseudobarbus swartzi has a higher number of scale rows along the lateral line, 34-37 vs. 25-33, and around the caudal peduncle, 13-17 vs. 10-12; it further differs from P. senticeps by lacking a conspicuous lateral stripe which terminates in a triangular blotch at the base of the caudal fin (Ref. 114782). While there is some overlap in scale counts between P. swartzi and P. afer, it is uncommon; Pseudobarbus swartzi has a higher number of lateral scale series, 34-37, than P. afer which has fewer lateral scale series, 29-35; the two species further differ in scale pigmentation pattern, P. afer has a band of pigment along the centre of the scales, leaving a clear band along the distal edges of the scale, and producing a distinct mesh or net-like pattern which is more conspicuous on the latero-ventral scales, this pattern is not evident in P. swartzi (Ref. 114782). Pseudobarbus swartzi differs from P. asper by possession of fewer larger scales, 34-37 lateral line scales vs. 35-45 and 13-17 caudal peduncle scales vs. 16-22 (Ref. 114782). Lack of prominent black spots and blotches on the body distinguishes P. swartzi from P. phlegethon (Ref. 114782). Description: A fusiform minnow with body slightly compressed laterally; predorsal profile convex, post dorsal profile straight and descending from origin of dorsal fin to caudal fin insertion; ventral profile more or less straight from tip of snout to pelvic fin origin (Ref. 114782). Head relatively short, length almost equal to body depth, its dorsal profile distinctly convex, particularly from its tip to interorbital area; mouth subterminal, its corner not reaching vertical through anterior margin of eye; barbel attached from behind the rictus of the mouth, barbel length variable, with some individuals having long barbels reaching or surpassing vertical through posterior edge of the eye, while other individuals have much shorter barbels; the eye is located closer to the tip of the snout than to posterior edge of the operculum, eye diameter shorter than snout length; snout blunt and moderately rounded (Ref. 114782). Scale rows along lateral line 34-37 ending at hypural, with 1-2 more scales to base of caudal fin; 6-7 scale rows between lateral line and dorsal fin origin; 4-5 rows between lateral line and pelvic fin origin, 5 rows between lateral line and anal fin origin; 16-20 predorsal scale rows; 13-17 scale rows around caudal peduncle; triangular naked patch between the gill covers and anterior base of pectoral fins, scales between pectoral fin origin and pelvic fin origin reduced and embedded; axillary scales of pelvic fin not prominent or elongate; scales between posterior edge of head and dorsal fin embedded and smaller than flank scales (Ref. 114782). Dorsal fin is inserted about mid-body, origin slightly behind vertical through origin of pelvic fin, with 3-4 unbranched rays and 7 branched rays, distal margin straight to slightly concave, posterior tip of depressed dorsal fin does not reach vertical through posterior base of anal fin; pectoral fins fan-shaped, larger in males than females, with 14-16 rays, tip of depressed pectoral fin almost overlapping with pelvic fin in large males, reaches 2 scales to base of pelvic fin in females; pelvic fin with 8 rays, origin slightly in front of dorsal fin origin, tip of depressed pelvic fin not reaching anterior origin of anal fin, except in mature males; anal fin with 3 simple rays and 5 branched rays, distal margin straight to slightly convex, origin closer to anterior base of pelvic fin than caudal fin base; in mature males, tip of depressed pelvic fin often surpass point of anal fin origin while they only reach up to the anus in females; caudal fin is forked, with 10+9 principal rays (Ref. 114782). Total vertebrae including Weberian apparatus 37-38, predorsal vertebrae including Weberian apparatus 12-13, precaudal vertebrae including Weberian apparatus 19-20, caudal vertebrae 17-18 (Ref. 114782). Colouration: Body golden-tan laterally, becoming darker dorsally, and lighter to white ventrally; base of fins bright red, operculum metallic gold (Ref. 114782). Alcohol preserved specimens are dark greyish above the lateral line, light grey or whitish below the lateral line and ventrally, breast of freshly preserved specimens silvery; mid lateral stripe present but comparatively obscure, black blotch at the base of caudal fin inconspicuous (Ref. 114782).
Biology:  Pseudobarbus swartzi inhabits perennial mountain streams with clear or peat stained water as well as cobble, pebbles and boulders (Ref. 114782). Remnant populations of the species are under severe threat from multiple human impacts including habitat degradation, complete water abstraction and potential invasion by alien fish predators and competitors that are now dominant in mainstream sections of the rivers (Ref. 114782).
IUCN Red List Status: Vulnerable (VU); Date assessed: 13 December 2016 (B1ab(iii,v)+2ab(iii,v)) Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Boden, Gert - 29.03.17
Modified by: Boden, Gert - 29.03.17

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