Melanochromis mossambiquensis, Konings-Dudin, Gertrud, Konings, Adrianus F. & Stauffer, Jay R., 2009

Konings-Dudin, Gertrud, Konings, Adrianus F. & Stauffer, Jay R., 2009, Descriptions of three new species of Melanochromis (Teleostei: Cichlidae) and a redescription of M. vermivorus, Zootaxa 2076 (1), pp. 37-59 : 50-53

Melanochromis mossambiquensis new species

( Figs. 6 , 7c ; Table 4)

Melanochromis sp. “auratus elongate” Konings 1995

Holotype. PSU 4555 , 76.1 mm SL, male; Mozambique, Lake Mala ẁi, Minos Reef , 12° 53.213’ S, 34° 45.013’ E, Stauffer and Konings, 15 Feb 2002.

Paratypes. PSU 4552 , 17 , 49.4–74.9 mm SL, data as for holotype ; AMNH 246008 , 2 , 50.8–63.4 mm SL, data as for holotype .

Diagnosis. Melanochromis mossambiquensis is distinguished from its congeners, except M. auratus , M. dialeptos , and M. wochepa , by a steeper-angled vomer (72–80° vs. 35–53°). It is distinguished from M. auratus by a mid-lateral and a dorso-lateral black stripe that is narrower than the submarginal black band in the dorsal fin, while in M. auratus the submarginal dorsal stripe is narrower than those on the flank. The abdominal yellow stripes in M. mossambiquensis are thin and never cover the entire lower abdomen as they do in M. auratus . The lower lobe of the caudal fin contains black spots while that of female M. auratus is yellow without black markings. Male M. mossambiquensis are distinguished from those of M. auratus by the lack of a narrow, yellow mid-lateral stripe. Male M. mossambiquensis are distinguished from those of M. wochepa by a brown/black body with white dorso-lateral and mid-lateral stripes while that of male M. wochepa is blue without stripes. M. mossambiquensis is distinguished from M. wochepa by a shallower body as expressed in a shorter distance between the origins of the dorsal and anal fin (47.1–50.8 % vs. 49.6–54.5 % SL) and a shorter distance between the origins of the dorsal and pelvic fins (27.6–33.4 % vs. 30.1–36.4 % SL), and by a longer lower jaw (29.0–41.5 % vs. 26.7–32.5 % HL). It is distinguished from M. dialeptos by a more elongate body as expressed in a larger distance between the posterior dorsal and the pelvic fin origin (52.9–60.7 % vs. 49.8–55.8 % SL), a longer snout (29.2–40.3 % vs. 25.9–35.2 % HL), and by fewer rows of scales on the cheek (3 or 4 vs. 4–7).

Description. Morphometric ratios and meristic values appear in Table 4. Small, somewhat elongate species (mean BD 30.9% SL) with greatest body depth at base of third or fourth dorsal spine. Dorsal body profile gradually curving downward to caudal peduncle; ventral body profile increasingly tapering upward to caudal peduncle. Dorsal head profile rounded, curving almost continuously between snout tip and dorsal fin origin; eye (mean 32.1% HL) larger than depth preorbital and positioned entirely in anterior half of head; moderately steep, rounded snout and slightly retrognathous jaws; teeth on lower and upper jaws in 3–6 rows, with those of outer rows bicuspid and those of inner rows tricuspid. Teeth of lower pharyngeal bone tightly packed with none enlarged or rounded. Vomer in single specimen (Nkhungu Reef) at 72° with parasphenoid.

Dorsal fin with XVII–XIX (mode XVIII) spines and 7–9 (mode 8) soft rays. Anal fin with III spines and 6–8 (mode 7) soft rays. First 4–6 dorsal spines gradually increasing in length posteriorly with first spine less than ½ length of sixth spine; last 12 spines slightly increasing in length posteriorly with last spine longest; soft dorsal with rounded tip, fourth ray longest, not or about reaching base of caudal fin. Anal spines progressively increasing in length posteriorly; fourth or fifth ray longest, not reaching base of caudal fin. Caudal fin subtruncate to emarginate. Pelvic fin not reaching anal fin. Pectoral fin rounded, paddle-shaped, short, reaching vertical through base of 10 th or 11 th dorsal spine.

Flank scales large, ctenoid; abrupt difference to fine scales on breast; cheek with 3 or 4 (mean 3) rows of small scales. Upper branch of lateral line with 21–28 pored scales; lower branch 8–14. Small scales on proximal posterior margins of dorsal and anal fins and on proximal half of caudal fin.

Coloration. Breeding males: head dark blue/black; snout dark blue/gray with some individuals with paleblue interorbital band; post-orbital head with pale blue horizontal band behind eye to edge of gill cover. Body dark blue/black with dorso-lateral and midlateral pale blue stripes; area above dorso-lateral stripe dark blue/ black with light-blue highlights; caudal peduncle dark blue/black with pale blue midlateral stripe, upper part with pale blue highlights; belly and breast dark blue/black. Dorsal fin light blue with dark blue/black proximal band and yellow distal margin, wider in trailing part. Caudal fin dark blue/black with pale-blue rays and yellow distal margin. Anal fin black, with 1 or 2 orange/yellow ocelli and pale blue ventral border. Pelvic fins black with white/light-blue leading margin. Pectoral fins with dark gray rays and clear membranes.

Females: head gray/yellow with gray/white gular region and irregular orange/yellow markings, snout with two black interorbital bands. Body gray/white with narrow black midlateral and dorso-lateral stripes, irregular orange/yellow stripe between two stripes; gray/brown irregular band below base of dorsal fin; 2–4 irregular yellow stripes on abdomen. Gray-yellow dorsal fin with broad black submarginal band bordered with narrow white stripes, yellow lappets and few black spots in trailing portion. Caudal fin clear with many yellow, black, and pale-blue markings throughout; lower lobe with yellow margin. Anal fin yellow with pale blue proximal band and black pigment on anterior part. Pelvic fins yellow with narrow white leading margin and, in some individuals, indistinct gray band anteriorly. Pectoral fins clear.

Distribution. Melanochromis mossambiquensis occurs between Chuanga (12° 38.278’ S, 34° 47.264’ E) and Nkhungu Reef (12° 57.434’ S, 34° 45.498’ E) in Mozambique ( Fig. 1 ). The populations observed—but not collected—at Metangula and N’kolongwe ( Fig. 1 ) appear to consist of individuals with longer snouts and shallower bodies.

Field observations. Melanochromis mossambiquensis is very common at Minos Reef (type locality) and often gathers in foraging groups feeding from the aufwuchs of the small rocks of the intermediate (sand-rock interface) habitat. Males in breeding coloration are normally solitary and rarely join the foraging groups. Territoriality is rare, but quarrels between males in breeding coloration are common and mainly consist of chasing a competitor from the feeding site.

Etymology. The specific epithet refers to the species’ restricted distribution along the Mozambique shore of the lake.

Figures

FIGURE 1. Map of Lake Malaẁi with localities mentioned in the text.

FIGURE 6. Melanochromis mossambiquensis, holotype, PSU 4555, 76.1 mm SL, male; Minos Reef, Lake Malaŵi, Mozambique.

FIGURE 7. a. A non-territorial male Melanochromis kaskazini (approx. 105 mm SL) at Ngwazi, Lake Malaŵi, Tanzania; inset: a female (approx. 65 mm SL) at Nkanda, Lake Malaŵi, Tanzania; b. two males of Melanochromis wochepa (approx. 60 mm SL) at Lumessi, Mozambique; inset: a female (approx. 50 mm SL) at same location; c. a male Melanochromis mossambiquensis (approx. 70 mm SL) at Minos Reef, Mozambique; inset: a female (approx. 55 mm SL) at same location.