Haplochromis vonlinnei van Oijen & de Zeeuw 2008

Diagnosis: moderately large sized and moderately slender, macrognathic species; dorsal head profile smoothly curved; snout rather acute; teeth strongly curved; distinct mid-lateral band, broader in males than in females, and thinner and interrupted dorsal lateral band present; ripening male with snout and cheek brownish grey, gill cover and the rostral part of flank golden brown, and ventral side, belly, caudo-ventral part of flank and caudal peduncle blackish (Ref. 74923).Description: body moderately slender and moderately compressed; dorsal head profile with a slight bend at the tip of the premaxillary pedicel; cephalic line openings not enlarged, lateral line canals on lachrymal not visible; eye and pupil circular; mouth slightly oblique; lips slightly broadened; premaxilla not expanded medially; exposed part of maxilla non bullate, posterior tip reaching or just passing vertical through anterior eye margin; lower jaw isognathousor slightly prognathous, slightly protruding; rostral outline of lower jaw convex, mental area rounded; no mental prominence; lateral sides of lower jaw oblique; 5-6 vertical scale rows on cheek; scales on head and rostral part of dorsum cycloid; chest scales cycloid or slightly ctenoid laterally, cycloid ventrally; scales on remaining parts of body ctenoid; proximal 2/3 of caudal fin covered with small elongated, ctenoid scales; no scale sheath at the base of dorsal and anal fins; except in the holotype (a large, ripening male), dorsal and anal fins do not reach base of caudal fin, and pectoral and pelvic fins do not reach anal fin origin; lowermost 4 gill rakers on lower part of first gill arch reduced, cone shaped, uppermost 3 short with expanded heads, remaining ones short with simple heads; intestine length varies from 0.9-1.2 times standard length (n = 5); following the definitions of Zihler (1982) the arrangement of the digestive tracks of adults Type D (with backflap); oral teeth in the outer row moderately stout, conical and moderately acutely pointed unicuspids; premaxillary teeth strongly curved; as a consequence, apart from the most anterior placed ones, premaxillary teeth hardly visible; lower jaw teeth moderately curved; inner row teeth are smaller replica’s of outer row teeth; in both jaws inner row teeth strongly curved; dental arcade rounded in both jaws, with 2 inner rows in the lower jaw, 2-3 in the upper jaw and distance between outer row and first inner row slightly larger than distance between inner rows; 29-35 teeth in outer row of upper jaw, 22-25 in lower jaw; outer teeth regularly set at a distance equal to slightly larger than diameter of tooth base; outer row teeth in upper jaw recumbent; outer row teeth in lower jaw, rostrally erect to slightly procumbent, laterally recumbent; all inner row teeth strongly recumbent; dentigerous arm of premaxilla longer than ascending arm, with angle between arms 80° and both arms relatively broad; ventral outline of dentigerous arm of premaxilla slightly concave; mandible relatively stout; length/depth ratio of mandible 2.4; the tooth bearing part of mandible slightly less than half jaw length (Ref. 74923).Coloration: Live quiescent male: upper lip, dorsal part of snout and dorsal head surface dark grey; ventral snout, rostral part of cheek and gill cover silvery, caudal part of cheek white; black opercular blotch extended forward to caudal margin of eye; lower lip whitish; lower jaw, interopercular and preopercular pinkish; iris dark blue, thin inner ring golden yellow; dorsum and dorsal part of caudal peduncle dark grey, a black dorsal lateral line runs beneath dorsal fin just above lateral line; flank light yellow, caudal peduncle grey; broad, black mid-lateral band begins at operculum (rather indistinct on first two scales) and continues to base of caudal fin; branchiostegal membrane, chest, belly and ventral side white; dorsal fin greyish with dark grey lappets and many dark grey-red streaks between rays; caudal fin greyish hyaline, medially with black membrane, dorsally and caudally with dark streaks between rays, distal part ventrally bright red, dorsally grey with red flush; anal fin pink around spines, rayed part pinkish hyaline, except for area around 3 medium sized orange egg dummies which is darker grey; anal fin with 2-4 rather large, bright orange egg dummies with white inner ring and hyaline outer ring; pectorals hyaline, pelvics sooty laterally merging into hyaline medially (Ref. 74923). Live ripening male: ground colour of head grey; lateral part of lower lip lighter, caudo-ventral corner of cheek and operculum whitish; iris dark blue, thin inner ring golden yellow; black opercular blotch rostrally extended to preoperculum; dorsal part of upper lip and snout, dorsal head profile, dorsum and caudal peduncle dark grey; ventral side, belly and caudal part of flank dark grey; lateral part of chest whitish; rostral part of flank lighter grey; inner ring of eye golden yellow; broad, black mid lateral band begins at operculum and continues to base of caudal fin; black dorsal lateral line runs beneath dorsal fin just above lateral line; dorsal fin greyish with black lappets; caudal half of fin with wide black streaks between spines and rays merging into red spots on rayed part; caudal fin dark grey blue proximally, grey distally; medially with dark streaks between rays, dorsally and ventrally with dark spots between rays; anal fin black on proximal half, distal half reddish rostrally, hyaline caudally; 3 medium-sized orange egg dummies with thin white rim on caudal part of black proximal half; pectorals hyaline, pelvics dark grey to black (Ref. 74923). Live females: lips, snout and dorsal head surface brownish grey; cheek and gill cover silvery white; large, dark, opercular blotch broadly extended to preoperculum and more indistinctly to eye margin; preopercular area pinkish yellow; dorsal half of iris bluish grey, ventral half golden yellow; dorsal half with thin yellow inner ring; branchiostegal membrane, chest and ventral side white; dorsal part of flank and caudal peduncle grey with yellow flush, ventral part light yellow; distinct black mid lateral band from operculum to caudal fin base; on darker dorsum the interrupted dorsal lateral band is less distinct; dorsal fin yellowish grey with dark lappets and grey streaks between rays; caudal fin dark grey proximally, distal part hyaline greyish with yellow flush; anal fin transparent yellowish, with 2 darker yellow spots caudally on proximal part; pectorals hyaline, pelvics white (Ref. 74923). Preserved ripening male: head and body brownish, lower lip, interorbital area and area between dorsal lateral band and mid lateral band lighter ivory-brown; snout and lateral sides of lower jaw sooty; dorsal half of gill cover blackish; body with broad, irregularly shaped mid lateral band running from gill cover to caudal fin base and a thinner and much less distinct dorsal lateral band; traces of 6 vertical bars which are more distinct in light area between lateral bands and on rostral part of flank; vhe ventral half of flank and caudal peduncle dark brown to sooty caudally; dorsal fin dark hyaline, darker proximally with dark grey lappets; pectorals hyaline; pelvics black; anal fin hyaline, but sooty proximally and rostrally, with 3 dark rimmed, ivory egg dummies; caudal fin dark hyaline, rays brownish, darker streaks and spots between rays (Ref. 74923). Preserved females: head and body brownish, upper lip, snout, post orbital area, and dorsal parts of head and body darker; opercular blotch almost black; body with black, complete mid lateral band and incomplete dorsal lateral band; all fins hyaline; lappets of dorsal fin dark; mid lateral band continued on base of caudal fin, membranes between 3 medial fin rays also black (Ref. 74923).

Piscivore, feeding on small haplochromine cichlids (Ref. 74923).

Haplochromis vonlinnei is a species of cichlid endemic to Lake Victoria. It is greyish in color with a distinct mid-lateral band, and a rather slender shape. It feeds mainly on smaller fish. This species can reach a length of 15.9 centimetres (6.3 in) SL. The population of the species has declined due to the introduction of the Nile perch in the 1950s. It has not been recorded since 1980 and the IUCN lists it as "Critically Endangered" and considers it may already be extinct. This fish is named in honour of the Swedish naturalist, Carl Linnaeus.