Serranochromis cuanza Stauffer, Bills & Skelton, 2021

Family:  Cichlidae (Cichlids), subfamily: Pseudocrenilabrinae
Max. size:  18.1 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Africa: Cuanza River, below Capanda Dam, in Angola (Ref. 123822).
Diagnosis:  Dorsal spines (total): 15-15; Dorsal soft rays (total): 12-14; Anal spines: 3-3; Anal soft rays: 9-11. Diagnosis: The presence of ocelli throughout the anal fin of breeding males distinguishes Serranochromis cuanza from S. robustus and S. jallae in which the ocelli in breeding males are restricted to the posterior 4-5 membranes of the anal fin (Ref. 123822). The exposed teeth of S. cuanza differs from those of S. stappersi and S. altus, which possess small teeth that are buried in the lips; Serranochromis cuanza has an emarginate caudal fin, while S. macrocephalus, S. janus, and S. angusticeps have rounded caudal fins; the shorter jaw of S. cuanza, 44.3-52.8% of head length, separates it from S. spei, 53.5-57.2% of head length; Serranochromis cuanza has 36-37 lateral-line scales, while S. thumbergi possesses more than 39 lateral-line scales; the acute angle of the cleft of the mouth, 50-60° of horizontal, of S. meridianus delimits it from the 25° angle of S. cuanza; the long dark pectoral fins which reach past the middle of the dorsal fin separates S. longimanus from S. cuanza (Ref. 123822). The interorbital width of S. cuanza, 16.3-18.0% of head length, is narrower than that of S. cacuchi, 20.0-21.7% of head length; Serranochromis cuanza has a greater preorbital depth, 19.1-22.2% of head length, and snout length, 35.2-39.6% of head length, than S. swartzi, 16.2-18.9% and 29.6-31.9% of head length respectively; the interorbital width of S. cuanza, 16.3-18.0% of head length, is wider than that of S. alvum, 14.3-15.9% of head length (Ref. 123822).

Description: Body fusiform and compressed, deepest at origin of dorsal fin (Ref. 123822). Dorsal-fin origin at vertical through posterior edge of operculum, dorsal fin with 15 spines and 12-14 rays; dorsal spines increase to maximum length over 5-6 spines, lappets prominent; soft dorsal deep and obtusely pointed behind, extending to base of caudal fin; caudal fin broad, relatively short rectangular, little more than half the head length, emarginate; anal fin with 3 spines and 9-11 rays, origin behind mid body, closer to caudal-fin base than tip of snout, below vertical through base of ultimate dorsal spine, soft-rayed section with pointed hind edge, extending to base of caudal fin; pectoral fin with 12-14 soft rays, close behind gill slit, ventro-lateral on flanks, base near vertical, pointed paddle-shaped, not beyond pelvic fins; pelvic fins ventral with strong leading spine 2/3 length of fin, origin narrowly behind vertical through base of pectoral fins, reaching to anus and anterior base of anal fin (Ref. 123822). Caudal peduncle long, 5.3-6.3 times in standard length, 16-19% of standard length, length 1.3-1.5 times depth (Ref. 123822). Scales small, with 18-20 regular rows across flanks from dorsal-fin origin to anal-fin origin; 16 scale rows around the caudal peduncle, 36-37 in lateral line, pores complete; upper lateral line nearly straight, slightly curved, lower lateral line straight through mid-caudal peduncle; five or six scale rows between anterior dorsal and lateral line, two scale rows between soft dorsal and posterior end of upper lateral line; chest scales small reduced and irregular; pored scales posterior to lateral line 1-2, 7-8 cheek scales (Ref. 123822). Head triangulate, length slighter greater than body depth, 2.5-2.7 times in standard length, 36.4-39.5% of standard length; predorsal profile straight, angle 30°; eye large, horizontal eye diameter 21.3-30.9% of head length, vertical eye diameter 20.1-30.4% of head length, dorso-lateral in anterior half of head, entirely above level of the mouth and below the dorsal edge of the operculum; snout relatively long, greater than orbit-diameter, nares in mid-snout before orbits; lachrymal width equal to orbit diameter; cheek below and behind orbits deep with 5-6 rows of scales; post-orbit less than half length of head, interorbit subequal to orbit diameter, 14.3-15.9% of head length; mouth terminal, large, protractile, angle of closed jaw of holotype 25° below horizontal, posterior premaxilla to below anterior orbit, lips well developed (Ref. 123822). Teeth caniniform, exposed, narrowly spaced in two to three rows on upper and lower jaws (Ref. 123822). First branchial arch with 2-4,1,9-12 gill-rakers; gill opening large, curved from above level of eye to mid-ventrally through a vertical below eye (Ref. 123822).

Colouration: Head en body brown in preserved specimens; laterally with single thin mid-lateral band and 8-9 regular bars from dorsum to lower flank; dorsal fin with greyish brown membranes, rayed membranes with proximal dark spots and distal streaks; caudal fin brown; anal fin brown with light indications of egg spots; pectoral and pelvic fins plain light brown (Ref. 123822). In life, metallic silvery on sides from head to caudal peduncle, dorsum mixed coppery-olive, white ventral surface; iris a deep purple-charcoal to reddish around the black pupil; upper operculum with metallic golden tinge; opercular spot grey, metallic light blue over exposed maxilla; inter-spinous membranes of dorsal fin light grey with darker grey posterior edges, lappets tinged with red, soft rayed membranes with light and dark blocks proximally, plain greyish distally; caudal fin with light rays and pale grey membranes forming blocks proximally; anal fin an overall yellow cast with greyish infusion, 4-5 scattered greyish egg spots with lighter margins on medial and posterior membranes; pectoral fins colourless off-white; pelvic fins yellow infused with grey, spines dusted sooty grey (Ref. 123822).

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


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