Nothobranchius nubaensis Valdesalici, Bellemans, Kardashev & Golubtsov, 2009
Nothobranchius nubaensis
photo by Valdesalici, S.

Family:  Nothobranchiidae (African rivulines)
Max. size:  4.99 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Africa: residual pools of seasonal rivers of White Nile River basin in central Sudan and south-west Ethiopia (Ref. 82677).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 17-19; Anal spines: 0-0; Anal soft rays: 17-19. Diagnosis: Nothobranchius nubaensis can be distinguished from all other species of the genus by the following combination of characters: 17-19 dorsal fin rays; 17-19 anal fin rays; 29-30 scales in median lateral series; dorsal and anal fin with short filamentous rays in males; pelvic fins short, tips reaching the anus; orange-red head with 3 distinct oblique bars on the operculum; dorsal fin light blue with a pattern of irregular orange-red spots and elongated yellow spots in distal areas; anal fin yellow, light blue at base, with a pattern of orange-red spots; pelvic fins yellow with a pattern of orange-red spots; pectoral fins orange-red with a light blue margin; caudal fin orange-red, with short pale or dark red lines extending from fin base onto fin rays (Ref.82677). Description: Robust, deep bodied Nothobranchius with rounded snout; terminal mouth directed upward (Ref. 82677). Dorsal fin rays 17-19; anal fin rays 17-19; scales in median lateral series 29-30+2-3 on caudal fin base; cephalic squamation pattern variable (Ref. 82677). Anterior neuromast series of 'open' type; central series in shallow groove with low lobes and with 3 neuromasts; posterior cephalic neuromast series curved with 3 neuromasts; preopercular neuromast system in open groove, distal ridge overlapping opercle slightly; one neuromast on each scale of median longitudinal series (Ref. 82677). In males, body deep and moderalety compressed; dorsal profile slightly concave to nearly straight on head, convex from nape to end of dorsal fin base; ventral profile convex, slightly concave on caudal peduncle posterior to dorsal and anal fins; maximum body height occurring at the base of the pelvic fins; dorsal and anal fins shallow and rounded, tips with short filamentous rays; dorsal and anal fins with papillate contact organs, distributed over fin rays; pelvic fins short, tips reaching the anus; caudal fin subtruncate; branchiostegal membrane projecting from opercle, distal edge slightly wrinkled (Ref. 82677). Female smaller than male; body less compressed and less deep than in males; dorsal fin rounded; anal fin triangular with rounded tip; anal fin positioned more posterior; short snout and narrower caudal peduncle than in males; opercular membrane not projecting from opercle (Ref. 82677). Colouration: Males with body and head scales light blue with broad orange-red margin, creating a reticulated pattern on body; almost completely orange-red on head; lips, snout, throat, frontal and superior portion of head all orange-red; opercular region with three distinct oblique bars on the operculum, extending from the eye to the upper part of the head; branchiostegal membrane orange-red with light blue rim; dorsal fin light blue with broad dark red reticulation, forming approximately horizontal arch-like stripes, broad border with interrupted red pattern; some elongated yellow spots in distal areas; anal fin yellow, light blue at base, with pattern of large orange-red spots; spots in the middle of the fin dark red, distal spots orange-red; caudal fin orange-red with pale or dark red lines extending from base onto fin rays, some specimens having a faint dark red marginal band; pelvic fins yellow with orange-red spots, spots near base dark red; pectoral fins orange-red with light blue margin, some specimens with yellow spots and short dark or pale red lines extending onto fin rays; iris golden, with faint black vertical bar through center of eye (Ref. 82677). Females with body pale olive-brown, lighter brown to silvery ventrally; unpaired and paired fins hyaline; iris golden, with faint black vertical bar through center of eye (Ref. 82677). In alcohol males with body scales light brown to whitish, almost all scales with distinct red margin; dorsal and anal fins light brown to whitish with a pattern of red spots; caudal fin of a light pale red; pelvic fins light brown to whitish with red spots near base; pectoral fins of a light pale red; iris bluish (Ref. 82677). Females in alcohol with body light brown to whitish; opercular and ventral area yellowish; unpaired and paired fins whitish; iris bluish (Ref. 82677).
Biology:  Found in residual pools of seasonal rivers and rainwater filled depressions (Ref. 82677). The present disjunct distribution pattern of Nothobranchius nubaensis can be explained by the dynamics of the changing rain pattern and climatic conditions over the vast plains of central and southern Sudan and south-west Ethiopia (Ref. 82677).
IUCN Red List Status: Vulnerable (VU); Date assessed: 04 January 2019 (B2ab(iii)) Ref. (130435)
Threat to humans:  harmless


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