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Dorsal spines (total): 0-0; Dorsal soft rays (total): 10-10; Anal spines: 0-0; Anal soft rays: 21-23; Vertebrae: 36-37. Diagnosis: Alestopetersius conspectus, is distinguished from A. smykalai, A. leopoldianus, A. nigropterus, A. caudalis, and A. sp. "mbuji" in the possession of 12, vs. 10, circumpeduncular scales (Ref. 89102). It is readily distinguished from A. brichardi, A. compressus, A. hilgendorfi, and A. tumbensis in the possession of a caudal-fin pigmentation consisting of a median black band extending to the caudal-fin margin and flanked by dense black bands in both upper and lower fin lobes (Ref. 89102). Alestopetersius bifasciatus, which shares similar caudal fin pigmentation, is distinguished from A. conspectus by the absence of a broad mid-lateral band on the body, and in tooth morphology (Ref. 89102).
Description: Relative gracile and shallow-bodied, body depth 26.4-34.5% of standard length, greatest depth at vertical through pelvic-fin insertion (Ref. 89102). Head length 20.4-29.7% of head length, eye large, bony orbit diameter 28.2-37.2% of head length; dorsal head profile straight from upper lip to nape, gently convex from that point to dorsal-fin origin; dorsal body profile gently convex along dorsal-fin base to caudal-fin base, ventral body profile gently convex between isthmus and anal-fin base, caudal peduncle slightly longer than deep (Ref. 89102). Mouth terminal, lower jaw prominent and slightly prognathous; premaxilla with two teeth in outer row, each bearing five cusps, positioned opposite interspaces between and alternating with, four inner row teeth, each bearing 6-8 cusps; outermost premaxillary tooth is markedly compressed and elongate with 7 or 8 small evenly sized cusps and a low median cusp; dentary with four teeth in outer row, each bearing 6 or 7 cusps, outermost tooth smallest in jaw; no inner row teeth on dentary (Ref. 89102). Dorsal fin with 2 unbranched and 8 branched rays, anal fin with 3 unbranched and 18-20 branched rays; origin of dorsal fin slightly in advance of vertical through pelvic-fin insertion (Ref. 89102). Body covered with small, regularly imbricate scales; lateral line complete, with 31-34 pored scales to caudal flexion, 6.5-7 scale rows between lateral line and dorsal-fin insertion, 2.5 between lateral line and pelvic-fin insertion, 12 circumpeduncular scales (Ref. 89102). Twelve to 14 gill rakers arrayed along lower limb of first arch (Ref. 89102). Total vertebral count 36-37 (Ref. 89102).
Colouration: In alcohol, base body colouration pale creamy brown with darker basal crescents at contact zones of contiguous scales on dorsum; in males faint humeral stripe present above pectoral fin, but no trace of humeral stripe present in preserved females; in males a broad black band extends from behind opercle, thickening gradually to caudal peduncle base, then narrows and extends to posterior caudal-fin margin; distinctive broad black band in each caudal-fin lobe apart from flank central black band and are separated from it by white bands; remaining fins dusky hyaline, leading edge of pectoral fin dark brown or black; in females colouration similar but mid-lateral band and caudal-fin bands somewhat muted (Ref. 89102). In life all individuals are iridescent silver with greenish-copper reflections anterolaterally, becoming bluish on flanks and caudal peduncle; mid-lateral band is obscured anteriorly on body but clearly marked on caudal peduncle; markings on caudal fin as in preserved specimens but much of the white interspaces between black bands are bright orange (Ref. 89102). |