Raiamas salmolucius (Nichols & Griscom, 1917)
photo by FAO

Family:  Danionidae (Danios), subfamily: Chedrinae
Max. size:  16.37 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; pH range: 7.4 - 8,
Distribution:  Africa: restricted to main channel and the tributaries of the northern hemisphere of the Middle Congo basin, where it is widespread throughout the Aruwimi, Itimbiri, Tshopo, Lindi, Ubangi and Sangha rivers (Ref. 122357). Reports from Lower Congo (Ref. 57537) and Kasai River basin (Ref. 41591) refer to Raiamas brachyrhabdotos (Ref. 122357).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 12-12; Anal spines: 0-0; Anal soft rays: 16-17; Vertebrae: 38-40. Diagnosis: Within the Congo basin, Raiamas salmolucius is distinguished from R. batesii, R. kheeli and R. moorii by a lower number of lateral line scales, 42-46 vs. 68-70, 65-68 and 54-61 respectively; from R. longirostris by a greater head width, 36-43% of head length vs. 31%, a longer anal-fin base, 16.1-20.5% of standard length vs. 14.8%, and a deeper body, 19.8-23.3% of standard length vs. 16.5%; from R. buchholzi and R. christyi by the absence of a large dark spot at the base of the caudal fin vs. presence, and a longer dorsal-fin base, 14.1-14.9% of standard length vs. 10.1-12.0% and 10.4-11.6% respectively (Ref. 122357). Further, it is distinguished from the phenotypically similar species R. marqueti, R. intermedius and R. brachyrhabdotos by a longer head, 30.2-33.6% of standard length vs. 27.0-30.1%, 27.1-29.5% and 28.5-29.5% respectively; in addition, R. salmolucius is distinguished from R. marqueti by a shorter distance between the nostril and the eye, 5-6% of head length vs. 6-7%, overlap due to negative allometry, and the first two pigmented bars behind the pectoral fin being narrow and covering 1.5-2.0 lateral line scales vs. wide bars covering 2.5-3.0 lateral line scales, and from R. intermedius and R. brachyrhabdotos by a shallower body, 19.8-23.4% of standard length vs. 25.2-28.8% and 23.6-29.8% respectively, and a more or less horizontal predorsal profile vs. a convex predorsal profile (Ref. 122357). Outside the Congo basin, R. salmolucius is distinguished from all other species, except R. ansorgii, R. nigeriensis and R. senegalensis, by an intermediate number of lateral line scales, 42-46 vs. 36-38 in R. levequei, 58-63 in R. scarciensis and 39-42 in R. steindachneri; from R. ansorgii by a dorsal fin inserted slightly behind the insertion of pelvic fin, i.e. two or three lateral line scales between verticals through the anterior base of the dorsal fin and the pelvic-fin insertion vs. dorsal fin inserted well behind pectoral-fin origin, i.e. six lateral line scales; from R. nigeriensis by a longer head, 30.2-33.6% of standard length vs. 18.6-25.0%; and from R. senegalensis by a higher number of branched dorsal-fin rays, 9 vs. 8 (Ref. 122357). Description: Body elongated; greatest body depth at anterior dorsal-fin region; predorsal body profile almost straight (Ref. 122357). Head with slightly convex upper profile; snout pointed, slightly projecting beyond anterior margin of lower jaw; with mouth closed, distal tip of maxilla almost reaching to posterior orbital margin; fourth infraorbital bone almost equal in size to third infraorbital bone but extending well behind posterior border of the latter (Ref. 122357). Dorsal fin on posterior half of body, originating behind level of pelvic fin insertion; with posteriormost ray distinctly behind anal-fin origin; about 2-3 lateral line scales between verticals through dorsal-fin origin and pelvic-fin insertion; pectoral and pelvic fins set low on body in sub-horizontal plane, their bases oblique; posterior tip of pelvic fin not reaching anus; pelvic axial scale pointed, variously elongate, measuring 45.0-85.0% of pelvic-fin length; anal fin falciform, last ray about 29-35% of longest anterior ray and originating below level of last third of dorsal-fin base; caudal fin deeply forked, median rays about 31-35% of the outer longest rays, lobes of similar size, pointed and triangular; dorsal fin with 3 unbranched and 9 branched rays, anal fin with 3 unbranched and 13-14 branched rays; pectoral fin with 1 unbranched and 13-15 branched rays; pelvic fin with 1 unbranched and 8 branched rays (Ref. 122357). Scales bordering the caudal-fin base smaller than body scales (Ref. 122357). Colouration: In life, overall colour of body silvery with pinkish hue; dorsum somewhat darker than ventrum; anterior half of iris bright yellow; posterior half white; seven to nine black bars on flanks, each covering 1-2 lateral line scales; 2-4 bars anterior to dorsal fin, and 2 below and 4 posteriorly; left and right flank may differ by one bar; anterior bars slightly longer than posterior ones, with first two extending below lateral line in adults; in specimens less than 80.0 mm standard length, bars do not extend below lateral line; two last bars situated on caudal peduncle and nearly as high as wide; space between first 4-5 bars twice the width of bars for specimens less than about 100.0 mm standard length, and becoming wider, to more than 3 times the width of bars in larger specimens; number of vertical bars not increasing with increasing size of specimen; snout and dorsum of head metallic greyish; dorsal and caudal fins red with marginal black band; other fins light pink (Ref. 122357). In preserved specimens, overall body colour yellowish to brownish with lighter ventrum and with dark bars on body arranged as above (Ref. 122357).
Biology:  Found in river over a sandy substrate (Ref. 122357).
IUCN Red List Status: Least Concern (LC); Date assessed: 01 May 2009 Ref. (124695)
Threat to humans:  harmless
Country info:   
 

Entered by: Sa-a, Pascualita - 25.01.95
Modified by: Boden, Gert - 01.07.20

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