Dorsal spines (total): 16-18; Dorsal soft rays (total): 7-8; Anal spines: 4-6; Anal soft rays: 5-7; Vertebrae: 32-33. Diagnosis: Lamprologus markerti is readily distinguished from L. tigripictilis by the presence of 4-6 broad dark bars on the flanks vs. 7-10 narrow bars, and from L. werneri in the possession of 14 vs. 15 precaudal vertebrae (Ref. 97099). It differs from both L. tigripictilis and L. werneri in a reduced number of gill rakers on the first arch, 9-10 vs. 12-17; a longer head, 32.1-34.7% of standard length vs. 29.3-31.9 and 29.1-32.9% respectively; and a longer predorsal length, 33.0-35.9% of standard length vs. 29.3-32.7 and 28.5-32.6% respectively (Ref. 97099). Further, L. markerti lacks an intestinal loop present in both L. tigripictilis and L. werneri, and has a highly reduced infraorbital series often consisting only of the first infraorbital element (Ref. 97099).
Description: Body relatively shallow, 20.2-24.8% of standard length, greatest depth at level of first dorsal-fin spine (Ref. 97099). Head long, 32.1-34.7% of standard length, snout prominent, with well-developed, fleshy lips (Ref. 97099). Dorsal head profile rises at angle of 40-50° to mid-orbit, then rises steeply to nape; large males with a prominent, fat filled nuchal hump (Ref. 97099). Dorsal and ventral body profiles slightly convex to relatively deep caudal peduncle (Ref. 97099). Jaws isognathous, inner and outer row teeth in both jaws pointed unicuspids; single series of 8 enlarged, recurved, procumbent canines situated anteriorly on premaxilla, with largest pair displaced dorsolaterally; behind the procumbent canines a single row of slightly enlarged canines gradually taper in size beginning at midlength of premaxilla; outer row teeth extend almost entire length of both dentary and premaxilla; lower pharyngeal jaw wider than long, with straight ventral suture; usually 24-28 teeth in posterior row, symphysial teeth moderately robust, become slender laterally (Ref. 97099). Gill rakers markedly elongate, non-denticulate and slender; 9-11 rakers along the outer row of first gill arch; one hypobranchial, 4-6 ceratobranchial rakers, often one raker in angle of arch, and 3 or 4 epibranchial rakers (Ref. 97099). Spines in dorsal and anal fins gradually increase in length posteriorly; both fins with tapering filamentous extensions to middle of caudal fin, longer in mature males than females; caudal fin large, paddle-shaped with 14 branched rays, fin often appearing subacuminate in preserved specimens; pectoral fin short, not reaching anus; pelvic fins also short but somewhat produced, reaching just short of anus or to between anal fin and anus; second branched ray in pelvic fin longest in both sexes (Ref. 97099). Flank scales large, uniformly sized, and ctenoid; chest and cheek scaleless; scales on nape and above upper lateral line, to level of 7-9th dorsal-fin spine, markedly smaller than those on flanks; opercle and subopercle with few, scattered, deeply embedded cycloid scales; proximal half of caudal fin covered with small ovoid, ctenoid scales (Ref. 97099). Pored lateral line scales 34-36; upper and lower lateral lines usually overlap by 2 or 3 scales (Ref. 97099). Total number of vertebrae 32 or 33, comprised of 14 precaudal and 18 or 19 abdominal centra (Ref. 97099). Supraoccipital crest relatively low, with no frontal ridge extending to neurocranial lateral-line foramen; infraorbital series consisting of broad , plate-like first infraorbital bearing 5 inflated, sensory-canal pores; small second infraorbital element polymorphically present and, when present, often lacks tubular sensory canal (Ref. 97099).
Colouration: In life base body colouration of mature males mauve gray becoming pale silver ventrally; turquoise reflective streak under eye, on posterior of cheek, and extending over opercle; flank scales ringed with dark pigment strongly contrasting with silvery central field; 4 or 5 dark vertical bars of uniform thickness, originating at base of dorsal fin and extending over flanks but not reaching to ventrum (Ref. 97099). Dorsal, anal and caudal fins proximally covered with alternating pale and dark spotting; pectoral fin clear, pelvic fin pale silver along distal margin; scaleless dark, opercular spot obscured by turquoise iridescence (Ref. 97099). In preservation, base body colouration creamy brown, slightly darker dorsally becoming pale cream ventrally; 4-5 dark vertical bars on flanks, and flank scales ringed with brown pigment contrasting with pale cream central field; dorsal and anal fins brown with alternating pale and dark maculae variously evident, but always present; caudal fin membranes with conspicuous rows of maculae, strongest proximally (Ref. 97099). All fin spotting more prominent in mature males than in females and juveniles (Ref. 97099).