Haplochromis simba, Vranken & Steenberge & Heylen & Decru & Snoeks, 2022

Vranken, Nathan, Steenberge, Maarten Van, Heylen, Annelies, Decru, Eva & Snoeks, Jos, 2022, From a pair to a dozen: the piscivorous species of Haplochromis (Cichlidae) from the Lake Edward system, European Journal of Taxonomy 815, pp. 1-94 : 29-34

Haplochromis simba sp. nov.

urn:lsid:zoobank.org:act:266E8987-E220-4EC4-AD72-0A46BE085EC8

Figs 1–2 , 14–16 ; Table 1

Differential diagnosis

Species with a piscivorous morphology; premaxillary pedicel and mental prominences strongly developed; outer oral teeth few and large [UOT 22–31 (median 27)]; dominant males yellow with an orange anterior part of flank.

Amongst piscivorous species from the Lake Edward system, H. simba sp. nov. differs from H. latifrons sp. nov., H. mentatus , and H. glaucus sp. nov. by the combination of a narrower interorbital area [IOW 45.5–50.4 (mean 48.1) vs 50.9–63.3 (53.8–60.0) % HW] and a strongly developed vs absent or weakly developed mental prominence. It further differs from H. latifrons sp. nov. by a longer anal fin base [AFB 17.3–19.0 (18.0) vs 14.7–17.3 (15.7) % SL] and absence vs presence of a well-defined mid-lateral band; further from H. mentatus by a smaller number of outer upper jaw teeth [UOT 22–31 (27) vs 28–46 (36)] and dominant males yellow with an orange anterior part of flank vs green-yellow with a red anterior part of flank; further from H. glaucus sp. nov. by a narrower lower pharyngeal element [LPW 83.8–87.9 vs 93.3–95.1% LPL] and dominant males yellow with an orange anterior part of flank vs uniformly lightblue.

It differs from H. rex sp. nov. and H. aquila sp. nov. by the combination of a smaller number of scales between first anal-fin spine and upper lateral line (ULL-A 9–11 vs 12–16, rarely 11) and a strongly developed vs absent or weakly developed mental prominence. It further differs from H. rex sp. nov. by a larger number of longitudinal line scales (LongL 32–33 vs 34–38) and dominant males uniformly yellow with an orange anterior part of flank vs cream-coloured with an orange operculum and a light blue snout; further from H. aquila sp. nov. by a smaller eye [ED 26.7–29.5 (28.3) vs 30.0–31.5 (30.6) % HL] and dominant males yellow with an orange anterior part of flank and a yellow head vs uniformly light grey with a black head.

It differs from H. kimondo sp. nov., H. falcatus sp. nov., H. curvidens sp. nov., H. pardus sp. nov., H. quasimodo sp. nov., and H. squamipinnis by the combination of large vs small outer oral teeth and a smaller number of outer upper jaw teeth [UOT 22–31 (27) vs 39–79 (45–58)].

It further differs from H. falcatus sp. nov., H. curvidens sp. nov., and H. pardus sp. nov. by a deeper lacrimal [LaD 18.7–20.5 (19.5) vs 16.0–18.8 (16.7–18.0) % HL]; further from H. kimondo sp. nov. and H. quasimodo sp. nov. by a narrower head [HW 39.5–41.5 (40.8) vs 42.0–48.1 (45.1–45.3) % HL]; further from H. squamipinnis by absence vs presence of minute scales on proximal part of dorsal fin.

Etymology

Specific name from Swahili ‘simba’ for ‘lion’; referring to yellow body, orange cheeks that resemble manes, and predatory morphology.

Material examined

Holotype UGANDA • ♂, 105.8 mm SL; Lake Edward; 0°24′16.0″ S, 29°46′24.8″ E; 9 Nov. 2016; HIPE1 exped. leg.; bought at Rwenshama landing site; RMCA 2016.035.P.0225 .

Paratypes DEMOCRATIC REPUBLIC OF THE CONGO • 1 ♂, 98.4 mm SL; “Lac Edouard: Vitshumbi (au Nord)” [Lake Edward: north of Vitshumbi ]; 0°40′50.6″ S, 29°23′22.6″ E (inferred); 2 Jul. 1953; KEA exped. leg.; IRSNB 13488 .

UGANDA – Lake Edward • 2 ♂♂, 1 ♀, 97.9–105.5 mm SL; 0°24′16.0″ S, 29°46′24.8″ E; 9 Nov. 2016; HIPE1 exped. leg.; bought at Rwenshama landing site; RMCA 2016.035.P.0222 to 0224 • 1 ♀, 87.1 mm SL; Rwenshama , rocky shore; 0°24′05.7″ S, 29°46′35.1″ E; 25 Mar. 2017; HIPE2 exped. leg.; RMCA 2017.006.P.0356 • 3 ♂♂, 90.0– 100.3 mm SL; same collection data as for preceding; RMCA 2017.006.P.0357 to 0359 • 1 ♀, 109.0 mm SL; 0°24′16.0″ S, 29°46′24.8″ E; 24 Jan. 2018; HIPE3 exped. leg.; bought at Rwenshama landing site; RMCA 2018.008.P.0348 .

Description

Based on 10 specimens (87.1–109.0 mm SL); body shallow ( Table 1 ) and oval to slightly pyriform; caudal peduncle shallow ( Fig. 14 ). Head long, narrow, and with a straight to weakly convex dorsal outline and a weak concavity above eye; eye small and high on head; interorbital area narrow; cheek and lacrimal deep. Snout long, rounded in dorsal outline, acute in lateral view, and slopes gently at 30–45°; premaxillary pedicel average in length and strongly prominent. Jaws isognathous to prognathous, long, slim, very narrow, and rounded in dorsal view; gape large and slopes gently at 20–25°; maxilla extends to between verticals through anterior point of orbit and just past this point. Lower jaw relatively shallow and with a straight ventral outline in lateral view, mental prominence strongly developed, and lower jaw side steep with an inclination of 35–40° to horizontal in anterior view. Upper jaw expanded anteriorly and ventrally. Lips and oral mucosa thin. Neurocranium shallow, ethmo-vomerine block decurved, preorbital region very shallow (18–20% NL), orbital region shallow (26–28% NL), and supraoccipital crest shallow and wedge-shaped ( Fig. 15b ).

Outer oral teeth few, unicuspid, and very large. Necks stout, conical, and straight; crowns straight to weakly recurved, and acutely pointed. Dental arcades rounded. Outer teeth widely and irregularly set with neck-distances of 1–4 neck-widths. In upper jaw, 1–2 posteriormost teeth enlarged. Inner teeth small, recurved, unicuspid, and acutely pointed. Tooth bands very slender crescent-shaped with 1–2 rows of inner teeth, and narrow posteriorly until only outer row remains past ⅔ length of tooth band. Inner teeth widely and irregularly set on 1–2 outer tooth neck-widths from outer row; implantation erect in first row and recumbent in subsequent rows; in upper jaw, size decreases slightly buccally and posteriorly.

Lower pharyngeal bone long, very narrow, slim, and shallow over whole length ( Fig. 16 ). Pharyngeal teeth relatively large and slender; major cusps acutely pointed; cusp gaps concave; minor cusps and cusp protuberances very small. Teeth in two median longitudinal rows equal in size and form to lateral teeth, 12 in each row. Posterior transverse row with 16–18 teeth, implanted recumbently with a lateral inclination; major cusps weakly recurved, bluntly pointed, and laterally compressed; minor cusps mostly absent.

Chest scales small; transition to larger flank scales gradual. Minute scales on proximal half of caudal fin.

Caudal fin emarginate; dorsal and anal fins reach to between verticals through two scales anterior to and one scale posterior to caudal-fin base. Pectoral fin reaches to between anal opening and second analfin spine; pelvic fin reaches to between first and second anal-fin spines; first branched pelvic-fin ray elongated.

Ceratobranchial gill rakers in outer row of first gill arch short, stout, and simple; posteriormost rakers anvil-shaped to weakly bifid. Epibranchial gill rakers slender and simple.

Colouration in life

Dominant males: body yellow; operculum, cheek, and anterior part of flank orange; belly and chest white ( Fig. 15c ). Snout dusky; lower jaw and lips pink; eye with (dark) grey outer ring and silver to golden inner ring. Nostril and lacrimal stripes faint; mental blotch present. pectoral fin yellow; pelvic fin black; dorsal fin hyaline to dusky and with black lappets and a dusky posterior part; anal fin faint crimson and with 2–3 very large orange egg-spots with hyaline rings; caudal fin dusky and with a faint crimson ventral part and a maculated dorsal part. Non-dominant males: anterior part of flank, operculum, and cheek with pink sheen; anal fin with crimson anterior part and hyaline posterior part; caudal fin uniformly dusky.

Females and juveniles: body, operculum, and cheek yellow; belly and chest white; lacrimal and lower jaw pink; snout dusky; eye with (dark) grey outer ring and silver to golden inner ring ( Fig. 15d ). Nostril and interorbital stripes faint; mental blotch present. Pectoral, anal, and caudal fins yellow; anal fin with a white base; caudal fin with a dusky base; dorsal fin hyaline and with black lappets and a dusky distal part.

Preserved colouration

Body whitish; dorsum and cheek brown; belly, chest, and operculum white; snout dusky ( Fig. 15a ). Nostril stripe well-defined; lacrimal stripe and mental blotch present; interorbital stripe and nape band faint. Pectoral fin dusky; pelvic fin yellowish in females, black in males; dorsal fin dusky and with black lappets and sooty posterior part; anal fin yellowish and with 1–2 large egg-spots; caudal fin dusky and with a maculated dorsal part.

Distribution and ecology

Only known from Lake Edward, found in inshore areas over hard substrates. Based on its morphology, most probably a piscivorous species.

Figures

Fig. 1. The Lake Edward system, consisting of Lakes Edward and George that are connected through the Kazinga Channel. The catch localities of all examined specimens are indicated: Haplochromis sp. ‘latifrons’ (), H. mentatus Regan, 1925 (), H. sp. ‘rex’ (), H. sp. ‘simba’ (▼), H. sp. ‘glaucus’ (), H. sp. ‘aquila’ (), H. sp. ‘kimondo’ (●), H. sp. ‘falcatus’ (), H. sp. ‘curvidens’ (), H. sp. ‘pardus’ (), H. sp. ‘quasimodo’ (▲), and H. squamipinnis Regan, 1921 (█). The type localities of H. mentatus and H. squamipinnis are not shown as the exact locations are unknown.

Fig. 2. a. Differences in total number of outer teeth and premaxillary dentition between the macro- and microdontic groups of piscivores from the Lake Edward system.b. Schematic presentation of the dominant male colour patterns in life, in the various groups studied. For H. sp. ‘latifrons’ the female and for H. sp. ‘curvidens’ the non-dominant colour patterns are shown, as those of dominant males are unknown.

Fig. 14. Haplochromis simba sp. nov., holotype, ♂, 105.8 mm SL (RMCA 2016.035.P.0225). Drawn by N. Vranken.

Fig. 15. Haplochromis simba sp. nov. a. Photograph of preserved holotype (RMCA 2016.035.P.0225; 105.8 mm SL). b. X-ray image of holotype. c–d. Photographs of freshly caught specimens. c. Dominant male (RMCA 2016.035.P.0224; 97.9 mm SL). d. Female (RMCA 2018.008.P.0348; 109.0 mm SL) to illustrate the live colour patterns. The contrast was slightly enhanced.

Fig. 16. Haplochromis simba sp. nov. (RMCA 2016.035.P.0223; 105.5 mm SL). a. Dorsal view of the lower pharyngeal jaw. b. Lateral view of the lower pharyngeal jaw.