Labrochromis mawepili, Mahulu & Seehausen, 2025

Mahulu, Anna & Seehausen, Ole, 2025, Two new cichlid species of the genus Labrochromis from rocky reefs of Lake Victoria, Tanzania (Perciformes, Cichlidae), ZooKeys 1240, pp. 117-137 : 117-137

Labrochromis mawepili sp. nov.

Haplochromis (Psammochromis) "striped crusher" : Seehausen 1996; Seehausen et al. 1997.

Haplochromis "striped crusher" : Seehausen and Bouton 1998.

Labrochromis sp. "stone": Karvonen et al. 2018; Gobbin et al. 2020, 2021; Meier et al. 2023.

Type material.

Holotype. • NMBE 1111906 mature male, 126.2 mm SL, Lake Victoria, Makobe Island , Speke Gulf, Tanzania, O. Selz, July 2010 . Paratypes. • 16 specimens, 80.8–144.2 mm SL. All specimens are from Lake Victoria, Makobe Island , Speke Gulf, Tanzania. • NMBE 1111916 , 105.4 mm SL, one male, O. Seehausen & S. Mwaiko, 2005 . • NMBE 1111917 , 80.8 mm SL, one female, O. Selz, 6 th August, 2010 . • NMBE 1111908 , 110.6 mm SL, one female, O. Selz, 6 th August, 2010 . • NMBE 1111914 , 120.1 mm SL, one female, O. Selz, 21 st July, 2010 . • NMBE 1111911 , 123.3 mm SL, one male, O. Selz, 3 rd June, 2010 . • NMBE 1111909 , 120.8 mm SL, one female, O. Selz, 23 rd June, 2010 . • NMBE 1111907 , 99.8 mm SL, one male, O. Selz, 23 rd July, 2010 . • NMBE 1111910 , 101.3 mm SL, one male, O. Selz, 26 th July, 2010 . • NMBE 1111905 , 98.1 mm SL, one male, O. Selz, 3 rd June, 2010 . • NMBE 1111912 , 120.8 mm SL, one female, O. Selz, 23 rd July, 2010 . • NMBE 1111913 , 88.2 mm SL, one male, O. Selz, 23 rd July, 2010 . • NMBE 1111900 116.7 mm SL, one male, O. Selz, 8 th August, 2010 . • NMBE 1111901 144.2 mm SL, O. Selz, 5 th August, 2010 . NMBE 1111902 , 134.9 mm SL, one male, O. Selz, 2 nd August, 2010 . • NMBE 1111904 , 112.6 mm SL, one male, O. Selz, 23 rd July, 2010 . • NMBE 1111903 , 106.8 mm SL, one male, O. Selz, 23 rd July, 2010 .

Description.

Based on 17 specimens from Makobe Island, Lake Victoria, Tanzania (Table 1 ) including the holotype.

Habitus. Large growing robust species, relatively deep-bodied with broken mid and dorsolateral bands and vertical bars creating a broken chessboard pattern in both sexes. The dorsal head profile is straight to moderately concave with a heavy head appearance. Oblique mouth with neither enlarged nor thickened lips.

Oral teeth. Teeth in the outer tooth row slender, unicuspid to weakly bicuspid, distantly spaced, slightly recurved, their implantation in the lower jaw is somewhat procumbent (Fig. 6 E ). The inner series teeth are small, tricuspid, and are arranged in two rows anteriorly and anterolaterally in both jaws

Dental arcade and tooth band. Dental arcade rounded, not square shaped. Inner rows in both jaws usually separated from the outer row by a moderate gap. Two rows of inner teeth, anteriorly and anterolaterally in both jaws.

The lower pharyngeal bone jaw and dentition. The lower pharyngeal jaw is strongly hypertrophied and stout with strongly enlarged molariform pharyngeal teeth (Fig. 6 F ).

Scales and squamation. The flank scales are ctenoid, ovoid with vertical long axis, slender and somewhat higher than wide. Operculum; scaled with cycloid scales, cheek; fully scaled with cycloid scales, caudal peduncle; fully scaled, scales moderately ctenoid, the chest; is fully scaled with smaller cycloid scales compared to those on the flanks somewhat deeply embedded although not as deeply as in many other rock-dwelling cichlids. The size transition is gradual. The belly is entirely scaled, with scales moderately ctenoid and not distinctly smaller than on flanks and somewhat deeply embedded. Dorsal fin; scaleless, caudal fin; partially scaled with cycloid scales, anal fin scaleless and pectoral fin; scaleless.

Coloration. Melanin pattern in both sexes: Both adults and subadults exhibit a broken dorso lateral and broken mid-lateral bands, together with the 4 vertical bars creating a broken chessboard pattern. The broken chessboard pattern is more prominent in females and subadult males (Fig. 2 H, I ) while adult males more often have the lateral bands purely expressed (Fig. 2 G ). Male nuptial coloration: Adult males are metallic blueish on the posterior flanks, the mid flanks are purplish, anterior and posterior dorsum are greyish (Fig. 2 ). Dorsal fin is blue grey with numerous red maculae within the soft part of the fin. A nape band, supraorbital, intraorbital, hind-eye, preopercular and lachrymal stripes faint; lower lip with a greenish sheen. The caudal fin is blue grey with red streaks and maculae, and the anal fin is proximally blue grey, distally faint red with 5–10 orange egg dummies (Fig. 2 ). Preserved specimens of both sexes are brownish and retain their broken longitudinal bands and fin maculae.

Distribution and ecology.

Labrochromis mawepili sp. nov. is exclusively known from the Speke Gulf in Lake Victoria, Tanzania with one observation from the northern Mwanza Gulf. The species has been observed at Makobe, Ruti, Igombe, and Hippo islands (Fig. 1 ) The species predominantly inhabits offshore areas beyond 4 meters in water depth with gentle to modest slopes. At steeply sloping islands it is often associated with the gently sloping small boulders habitat at the base of the larger and steeply sloping rocks (Fig. 7 ) in depths of 10 meters and beyond. Females of Labrochromis mawepili sp. nov. are more commonly encountered than males, distinguishing it as one of the few rock-dwelling haplochromines with such a prevalence. Despite (or perhaps because of) sharing similar habitat affinities as L. mawe sp. nov., sympatry between these two species is rare and is only known from Hippo Island where L. mawe sp. nov. was frequently encountered in crevices among inshore rocks, while L. mawepili sp. nov. was only encountered once, ~ 10 m offshore in deeper water ( Seehausen 1996). Labrochromis mawepili sp. nov. coexists with Astatoreochromis alluaudi at all islands, but while L. mawepili sp. nov. occupies offshore areas beyond 4 meters depth, A. alluaudi tends to be more common in shallower waters.

Food.

Labrochromis mawepili sp. nov. is primarily preying on snails and ostracods, with occasional consumption of insect larvae, albeit to a lesser extent ( Seehausen 1996).

Breeding.

As for Labrochromis mawe sp. nov.

Diagnosis and affinities.

Labrochromis mawepili sp. nov. shares a comparable structural modification in pharyngeal dentition with other described Labrochromis species ( L. ishmaeli , L. humilior , L. pharyngomylus , L. teegelaari , L. mylergates , L. ptistes , L. mawe sp. nov.) and shares its rocky habitat association with L. mawe sp. nov. It differs from L. ishmaeli , L. humilior , L. pharyngomylus , L. teegelaari , L. mylergates , L. ptistes , L. mawe sp. nov. in color patterns and habitat association. Labrochromis mawepili sp. nov. exhibit broken longitudinal stripes and vertical bars while L. mawe sp. nov. displays vertical bars without longitudinal stripes. Male nuptial coloration of L. mawepili sp. nov. are shared with those of the blue morph of L. mawe sp. nov. (See above in diagnosis of L. mawe sp. nov.). L. mawepili sp. nov. possess a narrower interorbital width (23.3–27.9 % HL) than L. mawe sp. nov. (24.0–31.8 % HL), L. teegelaari (25.0–30.0 % HL) and L. mylergates (26.0–33.0 % HL). Longer snout (30.7–36.0 % HL) than L. ptistes (29.4–32.4 % HL), L. pharyngomylus (27.3–33.3 % HL), L. humilior (27.0–34.8 % HL), L. mylergates (28.0–33 % HL) and L. teegelaari (27.0–31.0); (Table 3 ; Greenwood 1980). Labrochromis mawepili sp. nov. possess smaller eyes (18.7–25.8 % HL) than ‘ H. ’ theliodon (24.1–26.8 % HL), L. ishmaeli (23.0–31.0), L. ptistes (26.5–32.4 % HL), L. pharyngomylus (23.0–31.8 % HL), L. humilior (27.0–32.5 % HL), L. mylergates (28.0–33.0 % HL), L. teegelaari (27.0–33.0 % HL), and slightly smaller than L. mawe sp. nov. (21.3–25.9).

Etymology.

Species name mawepili, from Swahili, mawe means stone and pili means second. Refers to similarity in habitat association between this species and L. mawe and the superficial resemblance with the latter.

Figures

Figure 1. Known occurrences of Labrochromis mawe sp. nov. and Labrochromis mawepili sp. nov. against the background of all sites sampled in Lake Victoria by the authors’ team. Rocky sites are characterized by rocky substrates, which include boulders of various sizes, slabs and blocks, and occasionally large pebbles. Demersal sites are non-rocky substrates, mostly soft bottom, sometimes sand. Each rocky site was sampled with a comparable fleet of gillnets of various mesh sizes (1–2 inches stretched mesh) set in the morning, usually between 8 and 9 am and pulled after 4–5 hours. Each demersal site was trawled for ten minutes, which amounts to a stretch of ~ 1 km long and 10 m wide.

Figure 2. From top left A male Labrochromis mawe sp. nov. blue morph Python Island B male Labrochromis mawe sp. nov. red morph Python Island and C female Labrochromis mawe sp. nov. Python Island D, E two males Labrochromis mawe sp. nov. Kissenda island and F female Labrochromis mawe sp. nov. Kissenda Island G, H two males Labrochromis mawepili sp. nov. Makobe island and I female Labrochromis mawepili sp. nov. Makobe island.

Figure 6. CT scans of the frontal aspect of oral jaws (top) and occlusial aspect of the lower pharyngeal jaws (bottom) of Labrochromis mawe sp. nov. and L. mawepili sp. nov. All are males. From top left, A, B (NMBE 1111873) L. mawe sp. nov., Python Island C, D (NMBE 1111893) L. mawe sp. nov., Kissenda Island E, F (NMBE 1111906) L. mawepili sp. nov., Makobe Island.

Figure 7. Photographs of the sampling sites of Labrochromis mawe sp. nov. (A, B) and Labrochromis mawepili sp. nov. (C, D) A Kissenda Island B Python Island C Makobe Island and D Ruti Island.