Hemibrycon metae Myers 1930

This species is distinguished from most of its congeners by the number of branched anal-fin rays (25-31vs. 15-24). Compared with the species sharing similar branched anal-fin rays counts, it differs from H. boquiae by the number of caudal peduncle scales (16 vs. 14), and by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5); from H. brevispini by the number of cusps of three anteriormost dentary teeth (5 vs. 3), and by absence of bony hooks in the caudal-fin rays (vs. presence); from H. cairoense by the number of lateral line scales (40-43 vs. 43-46), and by the number of cups of first dentary teeth (5 vs. 3); from H. dariensis by the absence of pigment in the distal tip of rays just above and below to middle caudal-fin rays; from H. dentatus and H. huambonicus by the number of lateral line scales (40-43 vs. 44-50); from H. divisorensis and H. surinamensis by the absence of a wide black asymmetrical spot covering base of caudal-fin rays; from H. inambari by the of gill rakers (19-21 vs. 16-18) and by the number of scales along anal-fin base scale sheath (10-19 vs. 6-10); from H. jabonero by the number of caudal peduncle scales (16 vs. 14), and the number of scale rows below lateral line (5-7 vs. 4-5); from H. jelskii by the size of humeral spot (5-6 vs. 7-9 horizontal series of scales); from H. polyodon by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5), caudal peduncle length (11.1-14.8 vs. 14.4-16.6% SL), and head length (22.1-25.0 vs. 20.9-22.9% SL); from H. quindos by the number of cusps of premaxillary inner row teeth (5-7 vs. 3-4); from H. raqueliae by the number of predorsal scales (14-16 vs. 10-13) and by the number of cusps of first maxillary tooth (3 vs. 5); from H. taeniurus by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5), and by the humeral spot size (5-6 vs. 4-5 horizontal series of scales) (Ref. 85819).

Dorsal soft rays (total): 8; Analsoft rays: 25 - 30; Vertebrae: 39 - 41

Hemibrycon metae Myers, USNM 228563, 2, 43.3–48.6 mm; Venezuela, Surce, Clavellino Reservoir

Hemibrycon sp., USNM 317772, 2, 44.0–59.2 mm; Peru, Madre de Dios, Alto Rio Madre de Dios basin.