Diagnosis: Nothobranchius kwalensis is distinguished from all other congeners of the N. melanospilus complex by the combination of the following morphological character states: lower jaw not anteriorly projecting beyond upper jaw vs. anteriorly projecting in N. prognathus; dorsal-fin origin anterior to anal fin origin in females vs. posterior in both sexes in N. melanospilus; pelvic fins medially in contact vs. bases medially united in males of N. prognathus; presence of two longitudinal series of scales on frontal region vs. three in N. prognathus; anterior supraorbital series of neuromasts divided in two sections vs. arranged in a single continuous row in N. melanospilus; mandibular neuromasts 14-16 vs. 17-21 in N. melanospilus; in females, few rounded black dots on anterior portion of flank vs. dots absent on anterior portion of flank in N. melanospilus; body depth 28.7-30.9% of standard length in males, 25.8% of standard length in female, vs. 32.7-35.5% and 32.1-33.4% of standard length respectively in N. prognathus; dorsal-fin base length 24.1-27.3% of standard length in males vs. 27.9-29.9% of standard length in N. prognathus; head depth 79.0-82.9% of head length in males, 69.5% in female, vs. 90.4-99.2% and 85.6-90.3% of head length respectively in N. prognathus; eye diameter 26.8-28.4% of head length in males, 27.1% in female vs. 20.9-25.9% and 21.1-24.4% respectively in N. prognathus (Ref. 119668).

Description: Dorsal and ventral profiles slightly convex from snout to posterior end of dorsal and anal-fin bases, about straight on caudal peduncle; body slender, compressed; greatest body depth at vertical just in front of pelvic-fin base (Ref. 119668). Jaws short, snout weakly pointed in lateral view; jaw teeth canine, numerous, irregularly arranged, outer teeth greater than internal teeth (Ref. 119668). Gill-rakers of first branchial arch 4-5 + 15-16; six branchiostegal rays (Ref. 119668). Dorsal and anal fins broad in males, extremely rounded, with short filamentous rays along distal margin, dorsal fin longer than anal fin; in females, dorsal fin rounded, anal fin sub-triangular and slightly longer than dorsal fin; caudal fin subtruncate; pectoral fin rounded, posterior extremity between pelvic-fin base and anus; pelvic fin small, tip reaching between anus and urogenital papilla; pelvic-fin bases medially in contact; dorsal-fin origin on vertical between base of first and third anal-fin rays in males, just anterior to anal-fin origin in females; dorsal-fin rays 14-16; anal-fin rays 16-18; caudal-fin rays 30-32; pectoral-fin rays 19-20; pelvic-fin rays 6; minute contact organs on first and second pectoral-fin rays in males; rows of papillate contact organs along two distal thirds of most rays of anal fin in males (Ref. 119668). Scales small, cycloid; body and head entirely scaled, except ventral surface of head; minute filamentous contact organs along posterior margin of scales on middle portion of flank and latero-ventral portion of head in males; body squamation extending over anterior 35% of caudal-fin base; no scales on dorsal and anal-fin bases; frontal squamation irregularly arranged in two longitudinal rows; longitudinal series of scales 29-30; transverse series of scales 9; scale rows around caudal peduncle 16 (Ref. 119668). Anterior supraorbital series of neuromasts arranged in two separate sections, each placed in shallow depression, the anterior section with two neuromasts, the posterior one with three; sometimes minute neuromast between depressions; posterior supraorbital series with four neuromasts placed in shallow depression; infraorbital series with 18-24 neuromasts, pre-opercular series 15-16, mandibular 14-16; one neuromast per scale of lateral line (Ref. 119668).

Colouration: Male colouration in alcohol: trunk and head light brown, slightly darker on dorsum and lighter on venter; branchiostegal membrane dark grey; dorsal fin hyaline with transverse series of grey spots, anal fin hyaline; caudal fin yellowish hyaline with narrow black line along whole fin margin, slightly broader on posterior dorsal corner; pectoral fin hyaline, pelvic fin greyish hyaline with black tip (Ref. 119668). Female colouration in alcohol: trunk and head light brown, slightly darker on dorsum and lighter on venter; small dark brown spots irregularly arranged on whole flank, less concentrated in front vertical through pelvic-fin base; unpaired fins hyaline with small dark grey spots on basal portion; paired fins hyaline (Ref. 119668).