Labeotropheus chirangali, Pauers and Phiri, 2023

Pauers, Michael J. & Phiri, Titus B., 2023, Six New Species of Labeotropheus (Cichliformes: Cichlidae) from the Malaŵian Shore of Lake Malaŵi, Africa, Ichthyology & Herpetology 111 (2), pp. 263-292 : 278-284

Labeotropheus chirangali, Pauers and Phiri , new species

urn:lsid:zoobank.org:act:F4B4749E-26C3-4C2F-BB47- 09AC6CFEF06D

Figures 6 , 10 , 11 ; Tables 7, 11, 12

Holotype.— SAIAB 211378, adult male, 97.8 mm SL, Malaŵi, Lake Malaŵi, Mphanga Rocks, –10.4328123, 34.2783040, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018.

Paratypes.— FMNH 145012, 1 male, 94.9 mm SL, 1 female, 100.8 mm SL, Malaŵi, Lake Malaŵi, Mphanga Rocks, –10.4328123, 34.2783040, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018; MPM Fi50076, 12 males, 3 females, 72.4–109.4 mm SL, Malaŵi, Lake Malaŵi, Mphanga Rocks, –10.4328123, 34.2783040, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018; SAIAB 211379, 1 male, 92.3 mm SL, 2 females, 74.3 and 84.9 mm SL, Malaŵi, Lake Malaŵi, Mphanga Rocks, –10.4328123, 34.2783040, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018.

Diagnosis.— Labeotropheus chirangali differs from the robust Labeotropheus , except L. chlorosiglos and L. candipygia , due to its slender body (26.6–33.2% SL vs. 35.2–41.6% in L. fuelleborni ; 33.8–41.5% in L. aurantinfra ; 35.2–41.5% in L. obscurus , new species; 37.4–40.6% in L. alticodia ; and 34.3– 42.0% in L. artatorostris ). Labeotropheus chirangali has a slenderer body than L. chlorosiglos and L. candipygia , although its range of body depth partially overlaps with those of these species (31.9–34.7% in L. chlorosiglos ; 31.9– 38.6% in L. candipygia ). There are additional morphometric differences between L. chirangali and both L. chlorosiglos and L. candipygia , although some of the ranges overlap. Labeotropheus chirangali differs from both L. chlorosiglos and L. candipygia by shorter distances between the tip of the snout and the origin of the dorsal fin (28.4–32.7% SL vs. 31.2– 34.4% in L. chlorosiglos ; 32.2–36.8% in L. candipygia ), between the origin of the dorsal fin and the origin of the anal fin (32.2–51.5% SL vs. 51.3–54.6% in L. chlorosiglos ; 47.6–54.0% in L. candipygia ), and between the origin of the dorsal fin and the attachment of the pelvic fins (28.6–33.4% SL vs. 33.0–36.0% in L. chlorosiglos ; 32.7–38.8% in L. candipygia ). Additionally, L. chirangali has a greater width between the opercular tabs (15.1–17.8% HL vs. 14.7–15.7%) than L. chlorosiglos .

Labeotropheus chirangali differs from the other slender-bodied Labeotropheus primarily due to the nuptial coloration of the males. Male L. chirangali have a dark blue head, flank, and ventrum, and the scales in this region may have small ochreous-orange highlights. Above this extensive dark blue patch, male L. chirangali have a bright sky-blue dorsum; this pigmentation extends onto the dorsal fin. The tips of the dorsal fin are yellow, as is the trailing edge of this fin; the anal fin and the pelvic fins are the same bright sky blue as the dorsal fin. Many of the morphometric and meristic values of L. chirangali overlap with those of the other slender Labeotropheus , although there are some distinctions. Labeotropheus chirangali differs from L. trewavasae due to a larger snout pad (13.6–19.4% HL vs. 10.3–14.2%), a wider lower jaw (39.0–49.5% HL vs. 34.7–43.9%), fewer rows of teeth in the lower jaw (3–5 vs. 5–6), and more infraorbital neuromasts (14–38 vs. 8–25). Labeotropheus chirangali differs from L. simoneae due to a greater rostral length (39.2–47.6% HL vs. 34.3–43.0%), a larger snout pad (13.6–19.4% HL vs. mean 9.5–15.9%), and fewer overlapping lateral line scales (0–3 vs. 4–5). Finally, L. chirangali differs from L. rubidorsalis , new species, due to a smaller distance between the tip of the snout and the origin of the dorsal fin (28.4–32.7% SL vs. 31.4– 35.0%), a greater distance between the insertion of the dorsal fin and the attachment of the pelvic fins (54.1–58.8% SL vs. 49.5–55.1%), a smaller preorbital depth (23.4–28.4% HL vs. 26.6–32.9%), a larger snout pad (13.6–19.4% HL vs. 10.3– 14.2%), and a greater number of ceratobranchial gill rakers (7–10 vs. 5–8).

Description.— Morphometric data and meristic summarized in Table 11. Body compressiform and slender; body depth 27.5–30.3% SL. Flattened ovoid body shape, slightly deeper anteriorly than posteriorly. Body wide, slightly cylindrical in transverse cross section. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fan-shaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral line by 0–3 scales. Dorsal fin of typical length for a Labeotropheus (55.8–61.3% SL), 18–19 spines and 8–9 rays. Origin of dorsal fin posterior to or overlapping opercular tab. Dorsal-fin rays 3, 4, 5 long, reaching to hypural and beyond to caudal fin. Anal fin angular anteriorly with slight rounding to membrane posteriorly. Origin of anal fin opposite dorsal-fin spine 16; insertion of anal fin variable (anterior, opposite, or posterior) with respect to insertion of dorsal fin. Anal-fin rays 3, 4, 5 reach past hypural in most males; these only reach to mid-caudal peduncle in females. Caudal fin subtruncate. Pectoral fin short (19.3–24.7% SL), rounded, 13–14 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in the majority of specimens. Pelvic-fin ray slightly produced and filamentous in males and females. Pelvic-fin attachment opposite dorsal-fin spine 4 or 5.

Head short but deep for a slender Labeotropheus . Head profile moderately to strongly concave with prominent snout. Snout of typical length but wide (34.7–40.2% HL) with protruding snout pad (13.6–19.4% HL). Cheek with 3 scale rows. Infraorbital pores 9–10, with 14–38 neuromasts among them. Oral jaws long and wide. Oral teeth tricuspid and closely set on both upper and lower jaws; 6–11 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 7–10 ceratobranchial and 1–3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato- and epibranchial rakers.

Coloration of males.— Head and dorsum blue, varying among individuals from dark navy blue to lighter sky blue. Ground color of scales along flank and caudal peduncle blue, typically matching head and dorsum; i.e., males with sky blue head and dorsum have sky blue ground color along flank. Opercular tab black with metallic green sheen. 11 dark blue-black bars along flank and caudal peduncle. Scales along flank and caudal peduncle typically with ochreous-orange dots near inserted portion, generally becoming more prominent on caudal peduncle; some individuals with ochreous orange on caudal peduncle only. Dorsal fin blue, matching blue color of dorsum; trailing edge and tips of dorsal fin ochreous orange. Caudal fin blue suffused with orange; trailing edge ochreous orange. Anal fin iridescent bluish white or bluish gray with 3–6 orange-yellow eggspots. Posterior portion of pelvic fin very pale orange with white leading edge; prominent black stripe between leading edge and posterior pigment.

In preservative, males uniformly gray or brown with 11 dark bars spanning flank and caudal peduncle.

Coloration of females.— Head and operculum brown; opercular tab black with faint green sheen. Ground color of flank and caudal peduncle light tan; 11 dark brown bars span flank and caudal peduncle. Scales of flank and peduncle with small orange dot near insertion of scale. Belly white. Dorsal fin grayish brown or gray. Caudal fin gray; thin orange trailing edge. Spinous portion of anal fin white or gray, rayed portion grayish brown with orange trailing edge; 1–2 small orange-yellow eggspots present on rayed portion of anal fin. Pelvic fin pale orange with white leading edge; thin black bar separates leading edge from posterior pigment.

In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across flank and peduncle on some specimens.

Multivariate analyses.— Due to the overlap of morphometric and meristic characteristics between L. chirangali and the other geographically proximate slender Labeotropheus , we performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphometric data of L. chirangali , L. simoneae , and L. trewavasae . These analyses were robust and significant ( Table 12). When the first morphological canonical function is plotted against the first meristic canonical function, L. chirangali is clearly distinct from L. simoneae and L. trewavasae ( Fig. 11 ).

Distribution.— Labeotropheus chirangali is endemic to the Malaŵian shore of Lake Malaŵi, and is known only from the Mphanga Rocks off the tip of the Luromo Peninsula along the northwestern shore of the lake.

Etymology.— Chirangali is the Chichewa word for beacon, referring to the navigational beacon present on Mphanga Rocks.

Figures

FIG. 6. Body depth–standard length relationships among L. fuelleborni, L. trewavasae, L. chlorosiglos, L. simoneae, and the three new species of Labeotropheus from the northwestern portion of Lake Malaŵi. (A) All seven species; (B) same plot as A, but L. fuelleborni and L. trewavasae are omitted for clarity. The ANOVA accompanying these data is in Table 7.

FIG. 10. Labeotropheus chirangali, new species. (A) Live male holotype (SAIAB 211378), 97.8 mm SL; (B) holotype after preservation; (C) live female paratype (MPM Fi50076), 84.9 mm SL.

FIG. 11. Plot of morphometric canonical function 1 vs. meristic canonical function 1 for L. chirangali, L. simoneae, and L. trewavasae.