Diagnosis: Haplochromis lobatus differs from all species of Haplochromis from the Lake Edward system by a combination of an elongated and slender snout, strongly pro- to isognathous jaws, deep lower jaw with blunt teeth, and lobed lips that are mostly enlarged medially (Ref. 126507). It can be confused with H. labiatus as both have lobed lips, a small gape, a curved upper jaw with a relatively long premaxillary pedicel, 82.4-116.3% of upper jaw length, stout and unicuspid outer teeth that strongly decrease in size laterad, and a lower jaw set anteriorly with procumbently implanted outer teeth, 40-70° to vertical; it differs from this species by a straight to concave vs. straight to convex head, and an elongated and slender vs. blunt and more broad snout; differs further in its trophic morphology: lower jaw slightly longer, 31.2-40.7% of head length vs. 27.7-34.3%, and more slender, 48.5-70.5% of lower jaw length vs. 71.4-92.4%, jaws iso- to strongly prognathous vs. iso- to retrognathous, and anteriormost outer teeth in lower jaw more widely set, 1-2 vs. 0-1 outer tooth widths between adjacent teeth, and with longer major cusps (Ref. 126507). Haplochromis lobatus resembles H. chilotes from Lake Victoria by its very slender and acute snout, lobed lips, and insectivorous diet; it differs by having larger eyes, eye diameter 28.5-34.2% of head length vs. 21.8-28.6%, a correlated shorter snout, 26.9-32.9% of head length vs. 30.8-38.4%, and iso- to strongly prognathous vs. isognathous jaws; it further differs in live colouration; flanks with faint vertical stripes vs. vertical and longitudinal stripes, flanks of dominant males uniformly beige to yellow vs. blueish with orange chest and greenish caudal peduncle, and anal fin of dominant males dusky to black with yellow to orange extensions vs. pale red in H. chilotes (Ref. 126507). Haplochromis lobatus resembles superficially H. paucidens from Lake Kivu by its lobed lips, but clearly differs by its acute vs. blunt snout and more slender lower jaw, 48.5-70.5% of lower jaw length vs; 76.0-90.7% (Ref. 126507).

Description: Body deep; head concave to straight; snout elongated, very slender, acute, and with an inclination of 30-45° (Ref. 126507). Jaws iso- to strongly prognathous, i.e., inner teeth in lower jaw in some specimens visible in dorsal view when mouth closed; gape small and with an inclination of 20-40°; maxilla extends to between nostril and anterior margin of orbit; lower jaw very slender, stout, anteriorly deep, posteriorly very deep, and with a rounded outline anteroventrally in lateral view; upper jaw stout, short, with dentigerous arm of premaxilla curving gently downwards, and with a long premaxillary pedicel in comparison to upper jaw length, 82.4-116.3% of upper jaw length; lips lobed with medial parts mostly enlarged and oral mucosa very strongly thickened (Ref. 126507). Neurocranium with relatively deep preorbital region, and with a deep and pyramidical supraoccipital crest (Ref. 126507). Chest scales small; transition to flank scales gradual; scales on longitudinal line 30-34, scales on upper lateral line 19-23, scales on lower lateral line 10-14, scales between dorsal fin and upper lateral line 5-8, scales between upper lateral line and anal fin 10-12, scales around caudal peduncle 16, scales between pectoral and pelvic fins 4-9, infraorbital cheek scales 2-5, postorbital cheek scales 8-10 (Ref. 126507). Outer oral teeth large, stout, relatively few, and deeply embedded in oral mucosa; necks straight, long, and cylindrical; crowns straight to slightly recurved, short, and stout; major cusps bluntly pointed and equilateral to subequilateral; minor cusps, if present, short and blunt; cusp gaps narrow; dental arcades long, acute, and very slender; lateral and posterior outer teeth regularly and closely set with 1/2-1 outer tooth width between adjacent teeth; anterior outer teeth widely and irregularly set on 1-2 outer tooth widths; lateral and posterior teeth with straight implantations and almost completely embedded in oral mucosa; four to eight anteriormost outer teeth in ower jaw large, procumbently implanted on anterior margin of lower jaw, 40-70° to vertical, and in all specimens unicuspid; outer teeth strongly decrease in size laterad, abruptly in lower jaw; lateral outer teeth uni- to weakly bicuspid; in small specimens of less than 80mm standard length often bicuspid; in large specimens of more than 95 mm standard length, 2-3 posteriormost outer teeth in upper jaw enlarged and more stout than adjacent teeth; tooth bands crescent-shaped and relatively slender with 2-4 rows of inner teeth anteriorly that narrow laterad, until only outer rows remain; inner teeth uni- to weakly tricuspid, bluntly pointed, and widely and irregularly set on 1/2-1 outer tooth width from outer rows; inner teeth anteriorly in first row large and stout, while decreasing in size posteriad; no teeth abraded (Ref. 126507). Lower pharyngeal bone triangular and equally deep over entire length; pharyngeal teeth slender with cylindrical to slightly constricted necks, bluntly pointed major cusps, concave major cusp gaps, and blunt minor cusps; teeth in posteriormost transverse row more stout, blunt, and weakly bicuspid; teeth in two median longitudinal rows stout (Ref. 126507). Caudal fin emarginate; dorsal and anal fins reach level between one scale anterior and one scale posterior to caudal fin base; pectoral fins reach level between genital opening and first anal-fin spine; pelvic fins between genital opening and third anal-fin spine (Ref. 126507). All ceratobranchial gill rakers in outer row of first gill arch unifid and short, posteriormost rakers rarely bi- or trifid in large specimens of more than 100 mm standard length; epibranchial gill rakers short and slender (Ref. 126507).

Colouration: Colouration in life of dominant males: body, cheeks, and operculum green to cream yellow; dorsum green; chest dusky; flanks of some specimens with 4-6 very faint and dusky vertical stripes; snout and lower jaw turquoise; lips beige to dusky; nostril, interorbital, supraorbital, and vertical preopercular stripes and nape band faint and ill-defined; pectoral fins hyaline to dusky; pelvic fins black; dorsal and anal fins dusky to black, dorsal fin anteriorly with black lappets, posteriorly with orange-red lappets, and maculated orange-red between branched rays; anal fin dusky wit yellow to orange extensions and 4-7 small orange egg spots, i.e., size of distance between rays, with black borders; caudal fin orange-red to bright red and with dusky base (Ref. 126507). Colouration in life of females and juveniles: body, cheeks, and operculum beige to yellow; dorsum with blue-green sheen; chest and belly white; flanks with 4-6 very faint and dusky vertical stripes; pectoral fins hyaline with yellow sheen; pelvic fins white; dorsal fin dusky and with black lappets and maculated orange between branched rays; caudal fin dusky with yellow to orange extensions and dorsal part faintly maculated; anal fin white and with yellow extensions and 3-5 orange spots that resemble egg spots (Ref. 126507). Colouration in alcohol: dorsum brown, ventral part of body silver-beige; body of dominant males uniformly dusky; flanks of some specimens with faint 4-6 vertical stripes; pectoral fins hyaline; pelvic fins hyaline in females and juveniles, dark in dominant males; dorsal, anal, and caudal fins dusky in all specimens; all with hyaline extensions and anal fin with 4-7 faint egge spots in dominant males; nostril, interorbital, preopercular, and lachrymal stripes and a nape band faint and ill-defined (Ref. 126507).