Labeotropheus obscurus Phiri & Pauers, 2023

Family:  Cichlidae (Cichlids), subfamily: Pseudocrenilabrinae
Max. size:  7.83 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Africa: Malawi.
Diagnosis:  Dorsal spines (total): 16-18; Dorsal soft rays (total): 7-9; Anal spines: 3-3; Anal soft rays: 7-8. Diagnosis: Labeotropheus obscurus differs from all other species of Labeotropheus due to the unusually drab and muted colouration of sexually mature males; male nuptial colour pattern dominated by grey and brown pigmentation, with some blue and orange highlights on scales and fins, as opposed to a nuptial colour pattern dominated by blue, orange, or red pigmentation (Ref. 128773). Labeotropheus obscurus differs from the slender-bodied Labeotropheus species, L. trewavasae, L. simoneae, and L. chirangali, but not L. rubidorsalis, due to its greater body depth, 35.2-41.5% of standard length vs. 26.3-33.4% in L. trewavasae, 26.9-30.8% in L. simoneae and 26.6-33.2% in L. chirangali; it typically has a greater body depth than L. rubidorsalis, although the ranges slightly overlap, 31.6-36.1% of standard length in L. rubidorsalis; overall, L. obscurus does have a deeper body than L. rubidorsalis as indicated by several other measurements akin to body depth, including the distance between the origin of the dorsal fin and the origin of the anal fin, 50.8-56.3% of standard length vs. 45.6-50.3%, the distance between the insertion of the dorsal fin and the insertion of the anal fin, 15.8-17.8% of standard length vs. 13.5-15.7%, the distance between the insertion of the dorsal fin and the origin of the anal fin, 30.3-33.2% of standard length vs. 27.6-30.3%, and the distance between the origin of the dorsal fin and the attachment of the pelvic fins, 35.4-40.5% of standard length vs. 31.5-35.4% (Ref. 128773). Labeotropheus obscurus has a distinctly larger eye diameter than several of the robust species of L.abeotropheus, 27.3-32.4% of head length vs. 23.7-26.6% in L. fuelleborni, 22.6-25.5% in L. chlorosiglos, and 24.9-27.5% in L. alticodia; it also has fewer rows of teeth in the upper jaw than all robust Labeotropheus except L. alticodia, 3-4 vs. 4-5 in L. fuelleborni, 5-7 in L. chlorosiglos, 5-8 in L. artatorostris, 4-6 in L. aurantinfra, and 4-6 in L. candipygia, and fewer teeth in the left side of the lower jaw, 20-26 vs. 31-43 in L. fuelleborni, 30-37 in L. chlorosiglos and 29-35 in L. alticodia (Ref. 128773).

Description: Body compressiform; body shape ovoid; body depth 35.2-41.5% of standard length and consistently deep throughout trunk; body relatively narrow at pectoral fin and opercular tab (Ref. 128773). 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 by 0-4 scales; anterior lateral line scales 21-25, posterior lateral line scales 11-15; dorso-lateral scale rows 8-10; pectoro-pelvic scale rows 10-13 (Ref. 128773). Dorsal fin 56.1-63.0% of standard length, 16-18 spines and 7-9 rays; origin of dorsal fin overlapping opercular tab; dorsal-fin rays 3, 4, 5 long, reaching to hypural and beyond to caudal fin; anal-fin shape variable, angular and kite-like in some specimens, angled anteriorly with slight rounding to membrane posteriorly in others; origin of anal fin opposite dorsal-fin spine 16 in majority of specimens; 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 midcaudal peduncle in females; caudal fin subtruncate; pectoral fin long, 22.8-28.3% of standard length, rounded, with 13-15 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 all males and most females; pelvic-fin ray is non-filamentous in some females; pelvic-fin attachment opposite dorsal-fin spine 4, 5 or 6 (Ref. 128773). Head long, 29.2-37.8% of standard length, depth typical for Labeotropheus; head profile moderately to strongly curved with slightly protruding snout; snout long but narrow; snout width 30.9-44.6% of head length with slight snout pad, 9.5-19.4% of head length; cheek with 3-4 scale rows; infraorbital pores 9, with 22-46 neuromasts among them; oral jaws long and narrow; oral teeth tricuspid and closely set on both upper and lower jaws; 4-10 tricuspid teeth on lateral portion of left upper jaw (Ref. 128773). Gill rakers stout, triangular, and widely spaced; 6-11 ceratobranchial and 1-3 epibranchial gill rakers on first gill arch; all specimens with 1 raker between the cerato- and epibranchial rakers (Ref. 128773).

Colouration: Colouration of males: ground colour of head, operculum, flank, and caudal peduncle grey; flank suffused with pale blue in some individuals; 11 darker bars extending across flank and peduncle visible in some individuals; scales of flank abdominal to lateral line, between operculum and caudal peduncle, with orange spots near insertion of scale; opercular tab black, overlain with metallic blue in some individuals; dorsal fin grey in most individuals, pale blue in males with pale blue flanks; dorsal fin with orange tips and thin orange trailing edge in all individuals; caudal fin grey with orange trailing edge; anal fin predominantly grey with orange pigment on spinous portion; rayed portion with yellow tips and trailing edge, 2-4 orange-yellow eggspots present; pelvic fin orange with white leading edge (Ref. 128773). Colouration of females: head, body, and caudal peduncle uniformly light grey, with 11 faint dark bars extending across flank and caudal peduncle; some individuals suffused with a faint metallic green; scales of flank and caudal peduncle with small orange spots close to insertion of scale; opercular tab black; throat and branchiostegals white; dorsal fin white with orange tips; some specimens with orange trailing edge; caudal fin brownish grey, some specimens with orange trailing edge; rayed portion of anal fin pale brownish grey with 1-2 yellow eggspots; spinous portion white; pelvic fin pale orange, with bright white leading edge (Ref. 128773). In preservative, males uniformly brown or dark grey with 11 dark bars spanning flank and caudal peduncle visible on some individuals; females uniformly dark brown or grey with 11 faint vertical bars visible across flank and caudal peduncle on some specimens (Ref. 128773).

Biology: 
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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