Nannocharax chochamandai Katemo Manda, Snoeks, Decru, Brecko & Vreven, 2023

Family:  Distichodontidae (Distichodus)
Max. size:  3.77 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; pH range: 7.03 - 8.44; depth range 1 - 2 m
Distribution:  Africa: Lower Lufira, Fungwe and Mwanza River (both smaller right bank affluents of the Upper Lualaba), Luvua basin and Lukuga basin in Democratic Republic of the Congo (Ref. 129519).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 14-15; Anal spines: 0-0; Anal soft rays: 11-12; Vertebrae: 37-38. Diagnosis: Nannocharax chochamandai can be distinguished from all its congeners by the following unique combination of characters: its body colouration, which consists of eight to 10 ovoid black blotches that overlie a longitudinal mid-lateral black stripes vs. largely unpigmented body with a black spot on the posterior portion of the caudal peduncle in N. hastatus, N. maculicauda and N. ocellicauda, six or seven rounded, well-spaced, mid-lateral black spots in N. gracilis, 17 black bars in N. fasciolaris, a broad black longitudinal band running on flanks along two rows of scales in N. latifasciatus, a thin black lateral band covering only the lateral line scales, extending from snout to median rays of caudal fin in N. taenia; a completely pored lateral line vs. incompletely pored in N. angolensis, N. dageti, N. lineostriatus, N. machadoi, N. minutus, N. monardi, N. multifasciatus, N. rubensteini, N. uniocellatus and N. wittei; 41-46 lateral line scales vs. 38-40 scales in N. altus, 37-40 scales in N. brevis, 36-37 scales in N. micros, 36 scales in N. ogoensis, 38 scales in N. pteron, 38-39 scales in N. schoutedeni, 52-57 scales in N. elongatus, 47-53 scales in N. lineomaculatus, 50-55 scales in N. niloticus and 50-56 scales in N. occidentalis; and a dorsal-fin origin that is situated before the pelvic-fin origin vs. origin situated behind the pelvic-fin origin in N. fasciatus, N. hadros, N. procatopus, N. reidi, N. rubrolabiatus, N. seyboldi and N. signifer or situated at the level of pelvic-fin origin in N. intermedius and N. parvus (Ref. 129519). Nannocharax chochamandai has a long distance between the anus and the articulation of the first anal-fin ray, 10.1-14.9% of standard length, vs. 0.9-1.9% in N. usongo and 2.2-3.8% in N. zebra; a high number of unbranched dorsal-fin rays, 11-12 vs. 9-10 in N. hollyi and N. ansorgii; a short pectoral fin, 21.6-28.4% of standard length and the dorsal fin translucent without band vs. 28.6-31.6% of standard length and dorsal fin with two brown bands in N. macropterus (Ref. 129519). Nannocharax chochamandai is most similar to N. luapulae and can be distinguished from it by a high number of branched soft rays in dorsal and anal fin, 11-12 and 8-9 vs. 9-10 and 5; a low number of lateral line scales, 41-46 vs. 49-55; a long pectoral fin, 21.6-28.4% of standard length, reaching the pelvic-fin insertion and being situated about mid-level of the dorsal-fin base, vs. 18.3-20.6% of standard length, not reaching the pelvic-fin insertion and being situated at the level of the anterior origin of the dorsal-fin base; a long pelvic fin, 24.3-30.6% of standard length, reaching the anal-fin insertion and being situated at the level of the last quarter of the dorsal-adipose fin distance, vs. 20.0-22.9% of standard length, not reaching the anal-fin insertion and being situated about mid-level the dorsal-adipose distance; and a long anal fin, 15.6-19.0% of standard length vs. 13.6-15.1% (Ref. 129519).

Description: Body slightly elongated and laterally compressed, oval in cross-section; profile of predorsal region convex; body profile straight to slightly convex from insertion of last dorsal-fin ray to caudal-fin origin; lower part of body convex; maximum body depth reached just in front of dorsal-fin origin (Ref. 129519). Head anteriorly pointed in lateral profile; mouth small and subterminal; eye large, situated on dorso-lateral part of head, closer to tip of snout than to posterior end of operculum; interorbital distance smaller than eye diameter; nostrils closer to anterior border of eye than to tip of snout (Ref. 129519). Dorsal-fin origin located anterior to midbody and slightly anterior to vertical through pelvic-fin insertion; about two or four lateral line scales between verticals through dorsal-fin origin and pelvic-fin insertion; distal profile of dorsal fin nearly straight; distal profile of pectoral fin slightly concave; third pectoral-fin ray longest, extending beyond anterior pelvic-fin insertion, remaining rays gradually decreasing in length; third pelvic ray also always longest; tip of pelvic fin passing beyond urogenital opening, reaching or falling short, about one or two scales, of anal-fin origin; specimens from Fungwe and Mwanza rivers with three anteriormost pelvic-fin rays slightly thicker than other rays; adipose fin well developed, its origin at level of vertical through last branched anal-fin ray; caudal fin bifurcates with equal-sized lobes or lower lobe slightly larger than upper; dorsal fin with 3 unbranched and 11-12 branched rays, anal fin with 3 unbranched and 8-9 branched rays, pectoral fin with 12-13 rays, pelvic fin with 9 rays (Ref. 129519). Lateral line complete, straight and at mid-lateral position, from behind operculum to middle of caudal-fin base; three or four lateral line scales extending on caudal fin and also smaller than scales below dorsal fin; scales on lateral line 41-46, scales between lateral line and dorsal-fin origin 4-5, scales between lateral line and pelvic-fin origin 4-5, predorsal scales 10-13, scales between anus and anal-fin origin 5-8, scales between dorsal and adipose fin 11-14, circumpeduncular scales 15-16 (Ref. 129519).

Colouration: Colouration in life: living or freshly caught specimens characterised by yellowish to pale-brown overall ground colouration of head and body; dorsal area of head and snout bright yellow from anterior portion of upper lip to tip of supraoccipital spine; head laterally with dark stripe running from tip of snout to anterior margin of eye; upper half of iris black, lower half white; white-yellowish ring around pupil; black spot on operculum; ventral region of head white; dorsal region of body darker than ventral region; scales on dorsal region of body with melanin along distal border resulting in overall reticulated colour pattern; mid-lateral part of flank with indistinct silver longitudinal stripe; eight to 10 vertical blackish bars on flank largely under lateral line, each covering two scale rows above the lateral line, two to three on the lateral line end up to four scale rows below the lateral line; number, position and shape of bars varying from one side to the other, but the difference in numbers never exceeding one bar; in general, two or three bars in front of dorsal fin, three ventral to dorsal-fin base, two or three between dorsal and adipose fins, and two on caudal peduncle; anterior bars slightly longer than posterior ones; two or three posteriormost bars nearly as high as wide; last bar on caudal peduncle extending slightly posteriorly over base of medial caudal-fin rays and partially confluent with precaudal spot; fins with transparent membranes and blackish rays (Ref. 129519). In preserved specimens, overall colour of body yellowish to brownish with lighter coloured venter; bars on flank and pigmentation on dorsal region scales more evident and turning brown in freshly preserved specimens than in living or freshly caught specimens (Ref. 129519).

Biology: 
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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