| Diagnosis: |
Diagnosis: Haplochromis vanoijeni is a small sized (less than 9 cm standard length), micrognathic species with generalized body profile, but with a relatively long and acute snout; because of the latter, and its relatively small interorbital width, the species bears some resemblance with species of the 'tridens' group; indeed, it has some tricuspid teeth rostrally in the outer row of the oral jaws (Ref. 85523). It differs from eight of the nine described species in the 'tridens' group in the colouration of sexually active males: dorsum and flanks in sexually active males of Haplochromis vanoijeni are bright red; both males and females have conspicuously silverish-white cheeks, contrasting with the remaining head colours, which is a unique character among Lake Victoria haplochromines (Ref. 85523). From Haplochromis tridens, of which the colouration of live, sexually active males is unknown, it differs in the following characters: the lower jaw is shorter, lower jaw length 40.9-44.7% of head length vs. 43.3-51.8%; a larger interorbital width, 17.6-20.5% of head length vs. 15.0-19.5%; in contrast to H. vanoijeni, H. tridens has a dorsal head profile that is interrupted by a prominent premaxillary pedicel, and a cephalic line system with prominent pores (Ref. 85523). Besides by its specific colouration pattern, H. vanoijeni can be distinguished from all described species in the 'tridens' group by its larger body depth, 33.1-36.2% of standard length vs. 30.6-33.6%; the lower jaw of H. vanoijeni is shorter, 40.9-44.7% of standard length, than tah of most described species in the 'trident' group, except for that of H. cryptogramma and that of H. plutonius (Ref. 85523).
Description: Generalized body profile; dorsal head profile straight to slightly curved, sometimes with a slight incurvation above the eye; premaxillary pedicel not or slightly interrupting the dorsal head profile (Ref. 85523). Mouth moderately oblique; lips not thickened; premaxilla not or slightly expanded medially; caudal part of the maxilla not bullate; the vertical through the caudal tip of the maxilla is passing through the eye; lateral snout outline prognathous and acute; lower jaw slightly to moderately protruding; mental prominence moderately to strongly pronounced; retro-articular processes of right and left mandible are touching each other, and interrupting the ventral body outline; eye circular to slightly elliptic, with rostrally an aphakic aperture; cephalic lateral line pores normal to slightly enlarged (Ref. 85523). Dorsal head surface, cheek and operculum covered with cycloid scales, gradually changing into ctenoid scales on the dorsum and flank; caudal fin base with cycloid scales; ctenoid scales on the remainder of the body (Ref. 85523). Pelvic fins reaching or surpassing the anal fin origin; first soft rays of pelvic fins not produced or slightly produced and filamentous; male anal fin generally reaching or surpassing the caudal fin origin; female anal fin not reaching the caudal fin origin; caudal fin outline subtruncate (Ref. 85523). The number of gill rakers on the lower part of the first gill arch are 8 to 10; the gill rakers are long, slender and flattened with some bifids and trifids; the two rostral-most rakers are reduced or small; the rakers on the first gill arch are generally touching each other (Ref. 85523). Premaxillary dentigerous arm slightly longer than ascending arm; the angle between the two arms is 79°; lower jaw slightly elongated; a small mental prominence is present; genrally the teeth of both premaxilla and lower jaw are unequally bicuspid, frequantly interspersed with distinct tricuspids; in the caudal part of the premaxilla small tricuspids and weakly tricuspids can be found; in bicuspid teeth, the shape of the major cusp is isoscelene to subequilateral protracted; a small flange can be present; the cusp gap is wide, the minor cusp is distinct; tricuspid teeth may sometimes have a protracted middle cusp; in labial view, the neck is moderate, the crown is slightly expanded; in lateral view, the crown is slightly compressed; the premaxilla outer row teeth are straight to slightly recurved, those of the lower jaw slightly recurved; the inner row teeth of both premaxilla and lower jaw are tricuspid; teeth are relatively small and slender (Ref. 85523). Dental arcade U-shaped; premaxilla and lower jaw have two to three inner rows anteriorly, occasionally four; there are 52-70 teeth in the outer row of the upper jaw; teeth in both jaws regularly set; the crown distance varies from 1/3 to 1 times the crown width, laterally somewhat closer set than rostrally; outer row teeth of premaxilla erect; lower jaw outer row teeth erect to slightly procumbent; inner row teeth of lower jaw recumbent to strongly recumbent, inner row teeth of premaxilla recumbent; in both jaws, a slight to distinct gap between outer row and inner rows is present (Ref. 85523). Lower pharyngeal element relatively slender when compared to that of Haplochromis elegans; as long as it is broad or slightly longer than broad; the dentigerous area is broader than long; the suture is straight (Ref. 85523).
Colouration: Live colouration of males: dorsal head surface, gill cover and major part of dorsum and flank bright red, caudally changing into brownish-yellow; snout, lips and lower jaw yellowish to brownish, sometimes some bluish-grey present; the eye has a dark outer ring and a golden inner ring; caudal peduncle brownish-yellow; cheek silverish-white, sometimes with a red flush; chest silverish-white with a blackish, yellowish or a reddish flush; belly brownish-yellow with a reddish or blackish flush; ventral side silverish to yellowish-brown; lachrymal stripe generally present, sometimes faintly, in some specimens extending over the eye; nostril stripe present, sometimes faint; sipraorbital stripe occasionally present; the opercular blotch generally faintly present; occasionally faint traces of vertical bars are present; sometimes more distinct; pectoral fins hyaline, pelvic fins black; dorsal fin rostrally red, caudally brownish-yellow with red streaks, lappets on rostral part dusky; anal fin greyish-white with one to two large yolk-yellow egg dummies surrounded by a dusky ring; caudal-most part of caudal fin dusky, the remainder brownish-yellow with a red flush (Ref. 85523). Live colouration of females: general impression is golden-yellow over a whitish ground colour; snout, lips and lower jaw yellowish to brownish; dorsal head surface and caudal peduncle yellow to brownish-yellow; dorsum and flank, a red flush may be present; cheek, gill cover, chest, belly and ventral side silverish-white; the eye has a dark iris with a golden inner ring; lachrymal stripe faintly present; opercular blotch as well as faint traces of vertical bars may be present; pectoral fins hyaline, pelvic fins dusky or hyaline; dorsal fin yellow, dusky streaks may be present at the base with red streaks above them; lappets dusky; anal fin greyish-white at base, remainder hyaline-yellow; yolk-yellow ocelli may be present; caudal-most part of caudal fin hyaline, remainder hyaline-yellow, fin may have dusky streaks (Ref. 85523). Preserved colouration of males: grey-brown to brown; chest and belly somewhat dusky; lachrymal stripe and opercular blotch present; nostril stripe generally present, sometimes faint; supraorbital stripe occasionally present; faint vertical bars may be present, in some specimens more distinct; pectoral fin hyaline-grey-brown, pelvic fins black; dorsal and anal fin hyaline-grey-brown; caudal fin slightly darker; lappets in rostral part of dorsal fin may be dusky (Ref. 85523). Preserved colouration of females: grey-brown to brown; opercular blotch present; lachrymal stripe if present, faint; faint vertical bars may be present; pelvic fins dusky to blackish; pectoral, dorsal and anal fins hyaline-grey-brown; caudal fin slightly darker; lappets in rostral part of dorsal fin may be dusky (Ref. 85523). |