Diagnosis: Bryconops munduruku differs from its congeners, except B. inpai and B. piracolina, by possessing a black adipose fin (vs. adipose fin hyaline in alcohol); it differs from B. inpai and B. piracolina by possessing a hyaline band on the black adipose-fin base (vs. entirely black adipose fin in B. piracolina and B. inpai); Bryconops munduruku differs further from B. piracolina by having a hyaline dorsal fin (vs. presence of a large black blotch on the dorsal-fin base); Bryconops munduruku differs from other species of the subgenus Creatochanes, except B. inpai, by possessing 2 humeral blotches (vs. lack of humeral blotch or humeral region with a single humeral blotch in B. humeralis and B. vibex); it differs further from B. inpai due to the uniform color pattern on the posterior portion of the side of the body (vs. presence of a dark stripe extending posteriorly from the half of the anal-fin base onto the base of the middle caudal-fin rays) (Ref. 104128).

Description: body shape compressed, greatest body depth located just anterior to dorsal-fin origin; dorsal profile of body slightly convex from snout tip to dorsal-fin origin; straight to slightly concave from dorsal insertion to adipose-fin origin, gently sloping to beginning of caudal peduncle; caudal peduncle concave along dorsal and ventral margins; ventral profile of head and body convex from lower lip to pelvic-fin origin, and straight from this point to anal-fin origin; ventral profile straight and posterodorsally inclined along anal-fin base; mouth terminal; posterior extension of maxilla reaching junction between 2nd and 3rd infraorbital bones; 3rd infraorbital moderately developed, reaching preopercle ventrally; supraorbital bone present; premaxillary teeth in 2 rows, with midcentral cusp more developed than remaining cusps; outer teeth row with 5* (9) or 6 (3) tricuspid teeth; inner tooth row with 5* (10) pentacuspid teeth; maxillary with 1 (2), 2* (15), or 3 (1) tri- or tetracuspid teeth on contralateral parts; dentary with 5 (2) or 6* (6) penta- or hexacuspid teeth, followed by 6 smaller conical teeth; dorsal-fin rays ii,8 (3) or ii,9* (28); 1st unbranched ray about 1/2 length of 2nd unbranched ray; dorsal-fin origin slightly ahead of mid-body, positioned vertically through anterior 3rd of pelvic-fin base; posterior margin of dorsal fin straight to slightly concave; adipose-fin origin approximately at vertical through base of 18th to 19th anal fin branched rays; principal caudal-fin rays i,8,8,i (7) or i,8,9,i* (23); lobes of caudal fin unequal, lower lobe slightly longer than upper lobe; dorsal procurrent caudal-fin rays 14 (5), ventral procurrent caudal-fin rays 13 (4) or 14 (1); pectoral-fin rays i,10 (15) or i,11* (15); tip of pectoral fin reaching slightly beyond half of distance between pectoral and pelvic fins; pelvic-fin rays i,7*(30); pelvic fin originating at vertical through middle of dorsal-fin base, reaching slightly beyond half the distance between pelvic and anal fins; anal-fin rays iii, 23* (16), iii, 24 (6), iii, 25 (6), or iii, 26 (2); anal-fin origin located posterior to vertical through base of last dorsal-fin ray; last unbranched anal-fin ray and 1st to 4th branched rays slightly longer than remaining anal-fin rays; distal margin of anal fin concave; lateral line reaching base of caudal-fin rays; longitudinal scales in lateral line 44 (6), 45* (18), or 46 (8); all scales of lateral line pored; scale rows between lateral line and dorsal-fin origin 7* (22) or 8 (8); scale rows between lateral line and pelvic-fin origin 3* (18) or 4 (12); predorsal scales 10 (9) or 11* (5), arranged in a regular series; scale rows around caudal peduncle 15 (5) or 16* (3); precaudal vertebrae 19 (5); caudal vertebrae 22 (1) or 23 (4); total vertebrae 41 (1) or 42 (4); supraneurals 7 (4); 1st dorsal fin pterygiophore located between 11th and 12th vertebrae; gill rakers of 1st gill arch 16 (5): 2 (5) hypobranchial, 7 (5) ceratobranchial, 1 (5) on cartilage between ceratobranchial and epibranchial, 6 (5) epibranchial; gill rakers setiform; branchiostegal rays 5: 4 (5) on ceratohyal and 1 (2) on epihyal (Ref. 104128).

Coloration: color in alcohol: overall ground coloration of body dusky brown to yellowish; dorsal profile of head and snout dark; infraorbitals, maxillary, and ventral region of opercle silver; infraorbital 5 and dorsal portion of opercle with scattered chromatophores; lips and anterior portion of maxilla with dense concentration of chromatophores; gular region light; dorsolateral region of body darkened; scales of lateral region of body with chromatophores concentrated on posterior borders; 2 humeral spots present; 1st humeral spot conspicuous, vertically elongated, extending over 3 rows of scales above lateral line and horizontally over 2 rows of scales; 2nd humeral spot inconspicuous, vertically elongated; its form resembling the number 3; dorsal-fin rays darkened from base to mid-section, light at distal portion; black adipose fin, but hyaline along its base; caudal fin with concentrated chromatophores on half nearest most external rays of ventral and dorsal lobes; pectoral, pelvic, and anal fins hyaline, with few scattered chromatophores (Ref. 104128). Color in life: general body color reddish on dorsolateral region above lateral line; light grey from lateral line to ventral scale series; upper portion of head, opercle, intraorbital bones, and maxilla dark grey; upper margin of orbit red; anterior and posterior margins yellowish; dorsal fin red from base to mid-length of rays; distally hyaline; black adipose fin, with narrow hyaline band at base; caudal fin red at base to mid-length of dorsal and ventral rays; distal region of lobes hyaline; pectoral and pelvic fins, as well as 1st anal-fin rays, yellow (Ref. 104128).