| Diagnosis: |
Dorsal spines (total): 16-16; Dorsal soft rays (total): 11-11; Anal spines: 3-3; Anal soft rays: 8-8. Diagnosis: This species differs from all other tilapia except Coptodon fusiforme in a shallower body 30.0-31.5% of standard length vs. 32.9-52.5% and from Coptodon fusiforme in having 8 instead of 9-12 lower lateral line scales (Ref. 90097). It differs from all tilapia except Coptodon rheophila by additional morphological and meristic characters: stout teeth in oral jaw vs. spatulate teeth in Pelmatolapia mariae and P. cabrae; median pharyngeal teeth of lower pharyngeal jaw never broadened with crest-like cusps as in Heterotilapia cessiana and H. buttikoferi; posterior pharyngeal teeth of lower pharyngeal jaw never clearly bicuspid as in Tilapia busumana, T. pra, T. brevimanus, T. sparrmanii, T. baloni, T. ruweti and T. guinasana; vertical bars broader not than lighter interspaces; possessing slender to spatulate teeth in oral jaws as in Coelotilapia joka; no densely scaled caudal fin (Ref. 90097). Compared to Coptodon congica, C. tholloni and Congolapia bilineata, it further differs from all Coptodon, excluding C. rheophila, by a combination of the meristic characters: number of dorsal-fin spines, 16 vs. 13-17, and rays, 11 vs. 10-13; number of scales on the upper, 21 vs. 17-23, and lower lateral line, 8 vs. 7-14; and number of gill rakers, 7-9 vs. 7-12, on first ceratobranchial, excluding gill rakers on cartilaginous plague; it differs from C. rheophila by a smaller eye diameter, 7.5-7.6% of standard length vs. 8.0-10.7%, a shorter predorsal distance, 31.1-33.6% of standard length vs. 34.2-38.2%, a longer length of the base of dorsal fin, 61.4-62.3% of standard length vs. 56.9-60.9%, and a shorter pectoral fin length, 22.2-24.0% of standard length vs. 25.1-28.3% (Ref. 90097). It differs from the tilapia related species Chilochromis duponti in no densely scaled caudal fin or comb-like, spatulate teeth; from Gobiocichla in having two unconnected lateral lines vs. one continuous lateral line, and from Steatocranus in not developing a hump on forehead, and in fewer dorsal spines, 16 vs. 19-22 (Ref. 90097). The new species shares all typical Coptodon characters, which are: lower pharyngeal jaw as long as broad with anterior keel shorter than or just as long as toothed area of jaw; posterior pharyngeal teeth more or less clearly tricuspid, but sometimes quadricuspid or pentacuspid, median pharyngeal teeth never broadened with crest-like cusps; first outer gill arch bearing 10-17 rakers; two unconnected lateral lines; only cycloid scales present; 22-30 scales in the longitudinal scale row; upper and lower outer teeth rows bicuspid in both jaws, inner rows with smaller tricuspid teeth in both jaws; isognathous or retrognathous jaws; stout teeth; caudal fin not densely scaled; 13-17 dorsal spines; vertical bars, never oblique and mostly branched; pointed pelvic fin; no hump on forehead; no visor like hanging pad in pharynx; only one supraneural associated with first neural spine (Ref. 90097).
Description: The new species appears to be a dwarf species with a maximum observed size of 85.1 mm standard length (Ref. 90097). Body extremely elongated and laterally compressed; dorsal head profile slightly convex from insertion of first dorsal spine to tip of upper lip; head length about one-third of standard length, snout outline obtuse; eye moderately large and interorbital width always larger than eye length; greatest body depth at level of first dorsal spine; dorsal profile, towards caudal, slightly posteroventrally curved, not straight; caudal peduncle always longer than deep; two unconnected lateral lines (Ref. 90097). All scales cycloid; upper lateral line extending from posterior margin of gill cover to approximately center of dorsal fin; one complete row of large and one row of smaller, dorso-ventrally compressed scales separating upper lateral line from the last dorsal spine; lower lateral line originating at level of first branched dorsal-fin rays, terminating midlaterally on caudal peduncle; one scale row between upper and lower lateral line; preoperculum scaled with three to four regular rows; no scales on dark opercular spot; chest scales smaller, slightly embedded scales; base of caudal fin with minute scales (Ref. 90097). First lower gill-arch, ceratobranchial, with 7-9 gill rakers and first upper gill-arch, epibranchial, with 4 gill rakers with a single gill raker on cartilaginous plug included in the latter number; total number of gill rakers on first gill-arch 11-13; ceratobranchial rakers slender, broader on base, pointed; gill rakers situated most ventrally on ceratobranchial gill-arch smaller than all other gill rakers (Ref. 90097). Base of pelvic fin slightly more anterior than base of dorsal fin; dorsal-fin base 61.4-62.3% of standard length, with 16 spines and 11 rays; first dorsal-fin spine always shortest, last spine always longest; longest spine always shorter than longest ray; last dorsal-fin ray most deeply branched; caudal-fin outline truncate or slightly emarginate; anal-fin base 15.7-17.4% of standard length; anal fin with 3 spines and 8 rays; third anal-fin spine always longest; last anal-fin ray most deeply branched; tip of longest anal-fin ray always crossing hypuralia; pelvic-fin length 22.7-30.7% of standard length; tip of longest pelvic-fin ray not crossing anus; pectoral-fin length 22.2-24.0% of standard length; pectoral-fin rays 13; dorsal and anal fin elongated and pointed, pectoral fin rounded (Ref. 90097). Jaws slightly retrognathous; upper and lower outer teeth rows in both jaws bicuspid; neck of anterior jaw teeth stout, crown brownish, expanded and cusps truncated with a wide cusp gap; two to three incomplete inner rows of smaller tricuspid teeth in both jaws; lower pharyngeal jaw as long as broad or somewhat broader, anterior keel shorter than toothed area; most posterior pharyngeal teeth tricuspid, few bicuspid, stout, slightly hooked and regularly arranged, especially at the last two-three rows of toothed area; these posterior bicuspid teeth are derived from a tricuspid type, and are different than a well-marked bicuspid type; dentigerous plate triangular; most teeth in anterior two thirds of toothed area approach the 'kukri' tooth shape with three cusps (Ref. 90097).
Colouration: In alcohol basic colour brownish; head and dorsal side dark brownish, ventral side light brownish to whitish; chest and belly whitish with a few darker areas; two lines of flank scales with light scale margins and a dark centre above a horizontal line at level of the lower lateral line; lower lip light brownish to whitish and upper lip darker coloured; five or six dark vertical bars on dorsum and sides, first bar at level of first dorsal spine and last two on caudal peduncle, not reaching belly, a nape band, a supraorbital stripe and a lachrymal stripe; vertical bars often not present; dark opercular spot; pectoral and pelvic fin transparent; anal fin and caudal fin light brownish; dorsal fin without a 'tilapia spot' (Ref. 90097). Life colour unknown (Ref. 90097). |