Labeotropheus aurantinfra, Phiri and Pauers, 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 : 269-273

Labeotropheus aurantinfra, Phiri and Pauers , new species

urn:lsid:zoobank.org:act:68D4FDCB-80DF-44E2-977A- A7A7678CE748

Figures 5–7 ; Tables 6–9

Holotype.— SAIAB 211375, adult male, 114.8 mm SL, Malaŵi, Lake Malaŵi, Chirwa Island, –10.4684007, 34.2811572, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018.

Paratypes.— FMNH 145010, 1 male, 98.4 mm SL, 1 female, 90.8 mm SL, Africa, Lake Malaŵi, Chirwa Island, –10.4684007, 34.2811572, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018; MPM Fi50071, 12 males, 9 females, 72.9–111.7 mm SL, Malaŵi, Lake Malaŵi, Chirwa Island, –10.4684007, 34.2811572, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018; MPM 50077, 5 males, 10 females, 64.8–107.5 mm SL, Malaŵi, Lake Malaŵi, Ndomo Gap, –10.4350479, 34.2643444, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Shaibu Fisha, 2 August 2018; SAIAB 211374, 1 male, 90.6 mm SL, 2 females, 88.8 and 98.1 mm SL, Malaŵi, Lake Malaŵi, Chirwa Island, –10.4684007, 34.2811572, Michael J. Pauers, Titus B. Phiri, Victor Nantunga, and Stuart M. Grant, Ltd, crew, 1 August 2018.

Diagnosis.— Labeotropheus aurantinfra differs from all other Labeotropheus due to the extensive distribution of orange pigmentation throughout the body, including the maxilla, the preopercular margin, the branchiostegals, the gular and anterior abdomen region, and the flanks; although orange pigmentation is more common and more extensive in males, it is also present in the same body regions in females. Labeotropheus aurantinfra differs from the slender-bodied Labeotropheus , L. trewavasae , L. simoneae , L. chirangali , new species, but not L. rubidorsalis , new species, due to its greater body depth (33.8–41.5% SL vs. 26.3–33.4% in L. trewavasae ; 26.9–30.8% in L. simoneae ; and 26.6–33.2% in L. chirangali , new species). While L. aurantinfra does have a deeper body than L. rubidorsalis , new species, the ranges overlap (33.8– 41.5% SL vs. 31.6–36.1%). Labeotropheus aurantinfra has a greater distance between the origin of the dorsal fin and the attachment of the pelvic fins (33.4–40.4% SL vs. 31.5– 35.4%), a shorter lower jaw (22.5–31.6% HL vs. 29.9–38.5%), more rows of teeth in the upper jaw (4–6 vs. 3–4), and a greater total number of gillrakers (10–15 vs. 9–11) than L. rubidorsalis , new species.

This primary distinction between L. aurantinfra and the other robust-bodied Labeotropheus is the unique distribution of yellow-orange pigmentation across the body, especially in the males. The morphometric and meristic values largely overlap with the other robust Labeotropheus , although there are some distinctions, including those noted for L. alticodia above. Labeotropheus aurantinfra has a typically greater distance between the tip of the snout and the origin of the dorsal fin than L. fuelleborni (31.8–37.4% SL vs. 30.7–33.8%), a typically greater distance between the origin of the dorsal fin and the insertion of the anal fin than L. fuelleborni (60.8–69.5% SL vs. 55.1–64.9%), and typically more anal-fin rays than L. fuelleborni (7–9 vs. 6–7). Compared to L. chlorosiglos , L. aurantinfra has a greater eye diameter (23.5–32.4% HL vs. 22.6–25.5%), a longer rostral length (36.1–51.1% HL vs. 34.7– 41.1%), a greater pectoral width (13.2–18.9% SL vs. 12.7– 14.3%), and a greater number of scale rows between the pectoral and pelvic fins (9–12 vs. 6–9). Labeotropheus aurantinfra differs from L. artatorostris due to its greater rostral length (36.1–51.1% HL vs. 22.9–43.7%), a larger snout pad (10.5– 19.4% HL vs. 7.4–16.1%), and more infraorbital neuromasts (25–40 vs. 12–36). Labeotropheus aurantinfra differs from L. obscurus , new species, due to a typically shorter lower jaw (22.5–31.6% HL vs. 27.6–40.4%), a greater number of rows of teeth in the upper jaw (4–6 vs. 3–4), and a greater number of teeth in the left half of the lower jaw (24–37 vs. 20–26). This species differs from L. candipygia , new species, due to a greater distance between the origin of the dorsal fin and the insertion of the anal fin (60.7–69.6% SL vs. 50.6–66.8%), and a greater head depth (86.0–116.6% HL vs. 87.9–108.1%).

Description.— Morphometric and meristic data summarized in Table 6. Compressiform body with expanded ovoid shape; depth typical for a robust Labeotropheus (33.8–41.5% SL), and body consistently deep throughout its length. Body wide at pectoral fin and opercular tabs. 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 long (56.3–62.9% SL); 17–19 spines and 7–9 rays. First dorsal spine anterior to or opposite opercular tab. Dorsal rays 3, 4, 5 long, reaching to hypural and beyond. Anal fin angular and kite-shaped. Anal rays 3, 4, 5 long in males, reaching past caudal peduncle to caudal fin; most female specimens with short anal-fin rays, reaching only to caudal peduncle. Anal-fin origin opposite dorsal-fin spine 14, 15, or 16; anal-fin insertion anterior to or opposite dorsal-fin insertion. Caudal fin subtruncate. Pectoral fin long and rounded, 12–14 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in most specimens, especially in mature males; pelvic ray slightly produced and filamentous in all specimens. Pelvic-fin attachment opposite dorsal-fin spine 5 or 6.

Head short (29.1–38.8% SL) and deep with strongly curved profile and prominent snout; some specimens with concavity above eye. Snout long and wide, typical of Labeotropheus , with long snout pad (10.5–19.4% HL). Cheek deep with 3–4 scale rows. Infraorbital pores 8–10 with 15–67 neuromasts among them. Oral jaws short and wide. Oral teeth tricuspid and closely set on both upper and lower; 5–11 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.— All males with orange pigmentation on maxilla, preopercular margin, branchiostegals, gular region, and anterior abdomen, extending across ventrum in most individuals. Opercular tab metallic blue-green or metallic green. Head, operculum, dorsum bright sky blue in most individuals, rarely a dull gray blue. Scales of flank and caudal peduncle sky blue or gray blue, ringed with orange; orange ring may be thin, with blue predominating, or may cover the entire scale. In some individuals, orange may extend over entire body, including head, flank, and caudal peduncle; in these individuals, head and dorsum with brown or greenish sheen. 11 faint bars visible across flank and caudal peduncle. Dorsal fin predominantly bluish white; proximal portion of dorsal fin may have orange patches extending from dorsum. Trailing edge of dorsal fin orange. Caudal fin blue proximally, grading to black at the distal end; thin yellow trailing edge. Anal fin white or whitish gray with several (3–8) orange yellow eggspots. Pelvic fin pale red or orange with bright white leading edge; prominent black band separating leading edge from posterior color.

In preservative, males uniformly dark brown or gray with 11 faint vertical bars across the flank and caudal peduncle on some specimens. Some individuals with brown spots or rings on scales of flank and ventrum.

Coloration of females.— Head, body, and caudal peduncle uniformly light gray, with 11 faint dark bars extending across flank and caudal peduncle. Opercular tab black with metallic green sheen. Orange pigmentation on maxilla, preopercular margin, branchiostegals, gular region, and anterior abdomen, though not as prominent as on males. Scales of flank and caudal peduncle with small orange spots close to insertion of scale. Throat and branchiostegals white. Dorsal fin whitish gray. Caudal fin brownish gray. Anal fin whitish gray with 1–2 yellow eggspots. Pelvic fin white or hyaline, with bright white leading edge and pale orange between. One female L. aurantinfra had an orange blotch (‘OB’) color pattern across entire body and all fins; ground color is pale orange with black, white, and darker orange spots of varying shape and size.

In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across the flank and caudal peduncle on some specimens. ‘OB’ female appears pale gray with black and white spots across body and fins.

Multivariate analyses.— Due to the overlap of morphometric and meristic characteristics between L. aurantinfra and the other Labeotropheus , we compared the body depth–standard length ratios of L. aurantinfra and its geographically proximate congeners ( Fig. 6 ). This ratio clearly places L. alticodia with the robust Labeotropheus , and distinguishes it from the slender L. simoneae and L. chirangali , new species, as well as the intermediate L. chlorosiglos ( Table 7). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphological data for L. aurantinfra , L. candipygia , new species, L. chlorosiglos , and L. fuelleborni . The canonical discriminant function analyses were robust and significant ( Table 8 ). When the first morphometric canonical function is plotted against the first meristic canonical function, L. chlorosiglos is distinct along both axes, but there is some overlap among L. aurantinfra , L. candipygia , new species, and L. fuelleborni ( Fig. 7A ). Similarly, when the first two meristic canonical functions are plotted, L. chlorosiglos is distinct along meristic canonical function one, and L. fuelleborni is distinct along meristic canonical function two, with some overlap between L. aurantinfra and L. candipygia , new species ( Fig. 7B ).

Despite the overlap among L. aurantinfra , L. candipygia , new species, and L. fuelleborni along the canonical function axes, we found important distinctions among these species in the craniofacial region. Specifically, we examined the width to length ratios of both the lower jaw and snout. Labeotropheus aurantinfra , L. candipygia , new species, and L. fuelleborni all differ in these ratios ( Fig. 8 , Table 9).

Distribution.— Labeotropheus aurantinfra is endemic to Lake Malaŵi, along the Malaŵian shore. It appears to be restricted to Chirwa Island and the nearby Ndomo Gap, between the tip of the Luromo Peninsula and Chirwa Island.

Etymology.— The specific epithet is a composite of the Latin adjective aurantiacum, meaning orange colored, and a second Latin adjective, infra, meaning below or underneath. This is in reference to the unique male nuptial color pattern, in which the ventrum, anterior abdomen, and branchiostegals feature orange coloration.

Figures

FIG. 5. Labeotropheus aurantinfra, new species. (A) Live male holotype (SAIAB 211375), 114.8 mm SL; (B) live holotype with dorsal fin elevated; (C) holotype after preservation; (D) live female paratype (MPM Fi50071) with ‘orange-blotch’ (‘OB’) color pattern, 88.7 mm SL; (E) live male paratype (MPM Fi50071) with gray blue coloration, 111.7 mm SL; (F) ventral surface of male from E showing orange throat and branchiostegals; (G) live male paratype (MPM Fi50071) with extensive orange pigmentation and green sheen on head and dorsum, 98.4 mm SL; (H) ventral surface of male from G showing orange throat and branchiostegals.

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. 7. Canonical function plots for the robust Labeotropheus from the Luromo Peninsula. (A) Morphometric canonical function 1 vs. meristic canonical function 1; (B) meristic canonical function 1 vs. meristic canonical function 2.

FIG. 8. Comparison of jaw and snout dimensions among L. fuelleborni and the two newly described robust Labeotropheus from northwestern Lake Malaŵi. (A) Lower jaw length versus lower jaw width; (B) snout length versus snout width. The ANOVA accompanying these data is in Table 9.