Nannocharax dageti Jerep, Vari & Vreven, 2014
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Family:  Distichodontidae (Distichodus)
Max. size:  4.42 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater,
Distribution:  Africa: Kasai, Lualaba and Luapula rivers in the middle and upper Congo River basin (Ref. 95523), and the Kafue River (middle Zambezi River basin) (Ref. 95523). Based on literature (Ref. 12524, 13337, 94654), also known from the upper Zambezi River (Ref. 95523).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 12-16; Anal spines: 0-0; Anal soft rays: 9-12; Vertebrae: 38-40. Diagnosis: Nannocharax dageti is distinguished from all its congeners except N. angolensis, N. gracilis, N. lineostriatus, N. luapulae, N. macropterus and N. taenia by the colouration pattern of a series of vertically elongated, rounded blotches that overlie a longitudinal midlateral dark stripe but are largely separate dorsally from the saddles extending to the dorsal midline (Ref. 95523). Nannocharax dageti differs from N. gracilis, N. luapulae, N. macropterus and N. taenia by possessing an incompletely pored lateral line vs. completely pored lateral line, and a caudal fin with a symmetrical colouration pattern on the lobes consisting of a dark spot at the base of each caudal-fin lobe not continuous with the dark spot over the base of the middle caudal-fin rays, and a series of dark spots forming a transverse stripe paralleling the distal margin of the fin about one-third the length of the lobe from its tip (Ref. 95523). Nannocharax dageti is distinguished from N. angolensis and N. lineostriatus by possessing 40-43 scales along the longitudinal line including the lateral line, vs. 34-39 in N. angolensis and 34-35 in N. lineostriatus; 36-41 pored scales along the lateral line, vs. 21-33 in N. angolensis and 6-9 in N. lineostriatus; and 38-40 vertebrae, vs. 36 in N. angolensis and 35-36 in N. lineostriatus. Description: Body elongate; becoming progressively compressed posteriorly to caudal peduncle (Ref. 95523). Dorsal profile of head rounded along anterior portion of snout; convex from that point to vertical through posterior naris, slightly convex from that point to tip of supraoccipital spine; profile of predorsal region of body straight to slightly convex to dorsal-fin origin; body profile convex along dorsal-fin base, straight to slightly convex from insertion of last dorsal-fin ray to adipose-fin origin, and straight to slightly convex along caudal peduncle (Ref. 95523). Ventral profile of head convex along anterior portion of dentary; slightly concave to slightly convex from that point to isthmus; ventral profile of body convex along ventral margin of pectoral girdle, variably convex from that point to pelvic girdle; convex to straight from pelvic-fin insertion to vertical situated anterior to urogenital papillae; concave along region of urogenital and anal openings, straight to convex from that point to anal-fin origin; then straight to slightly convex along anal-fin base to last anal-fin ray insertion and straight to slightly convex along ventral profile of caudal peduncle (Ref. 95523). Head anteriorly pointed in lateral profile (Ref. 95523). Eye large; situated on lateral surface of head; pupil ovoid with anterior emargination of iris (Ref. 95523). mouth subterminal; positioned posteroventral of tip of snout tip at horizontal through ventral margin of eye (Ref. 95523). Premaxilla with single row of 4 teeth; premaxillary teeth elongate, bicuspid, slightly distally expanded and gradually decreasing in size posteriorly (Ref. 95523). Dentary with single row of 5 or 6 teeth; dentary teeth elongate, bicuspid and slightly distally expanded; gradually decreasing in size posteriorly with posterior most tooth approximately one-half size of symphyseal tooth (Ref. 95523). Maxilla toothless, transversely flat and posteriorly expanded; ventral margin of maxilla slightly convex and posterior border rounded (Ref. 95523). Dorsal-fin origin located anterior to middle of standard length and slightly anterior to vertical through pelvic-fin insertion; distal profile of dorsal fin slightly convex; first branched dorsal-fin ray longest; posterior rays decreasing progressively in size; unbranched dorsal-fin rays 2-4, branched rays 10-12 (Ref. 95523). Distal profile of pectoral fin slightly concave; second branched ray longest and extending beyond rest of fin profile; tip of pectoral fin falling short of, or slightly surpassing, pelvic-fin insertion; pectoral fin with 1 unbranched and 9-11 branched rays (Ref. 95523). Distal profile of pelvic fin straight to slightly convex; second branched pelvic-fin ray longest, extending beyond rest of distal profile of fin; remaining rays gradually decreasing in length; tip of pelvic fin passing beyond urogenital opening but falling short of anal-fin origin; pelvic fin with 1 unbranched and 7-8 branched rays (Ref. 95523). Adipose fin well developed with origin along vertical through insertion of penultimate or ultimate branched anal-fin ray (Ref. 95523). Distal profile of anal fin convex anteriorly and slightly concave posteriorly with first branched ray longest; unbranches anal-fin rays 2-3, branched rays 7-9 (Ref. 95523). Caudal lobes of similar size and distally pointed; scales bordering caudal-fin base smaller than body scales; caudal-fin rays i,17,i (Ref. 95523). Scales ctenoid with serrations formed by separate, distally narrowing ossifications along free margin of each scale (Ref. 95523). Longitudinal scale row including pored portion of lateral line with 40-43 scales; posterior most one or two scales extending beyond point of flexure at posterior margin of hypural plate; lateral line straight, incompletely pored with 36-41 pored scales (Ref. 95523). Scale rows between dorsal-fin origin and lateral line 4-5; scale rows between pelvic-fin origin and lateral line 4-5; middorsal scales from tip of supraoccipital spine to dorsal-fin origin 9-13; scales from posterior terminus of dorsal-fin base to adipose fin 10-13; scales between anus and anal-fin origin 3-6; scale rows around caudal peduncle 12 (Ref. 95523). Colouration: In alcohol, overall ground colouration of head and body yellowish to tan; dorsal surface of head and snout dark from anterior portion of upper lip to tip of supraoccipital spine; lateral surface of head with dark stripe running from tip of snout to anterior margin of eye; patches of irregularly arranged, dark chromatophores over first infraorbital, infraorbital bones along posterior margin of eye and opercle; ventral region of head unpigmented (Ref. 95523). Dorsal region of body darker than ventral region; 6-10 dark saddles along dorsal midline of body; midlateral surface of body with dark, midlateral longitudinal stripe; series of 7-12 vertically elongated, rounded, dark blotches overlapping dark, midlateral longitudinal stripe (Ref. 95523).
Biology: 
IUCN Red List Status: Not Evaluated (N.E.) Ref. (124695)
Threat to humans:  harmless
Country info:   
 

Entered by: Boden, Gert - 29.04.14
Modified by: Boden, Gert - 06.05.14

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