| Main Ref. | Marinho, M.M.F., F.C.P. Dagosta and J.L.O. Birindelli, 2014 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks | Mature males with dorsal (31.6-44.9% of SL), pelvic (18.8-23.8% of SL) and anal fin (23.1-27.3% of SL) longer than females or immatures (28.1-32.9%; 15.8- 20.3%; 19.5-24.4%, respectively). Pelvic-fin tip extends from base of first to fifth branched anal-fin ray in mature males (vs. not reaching anal fin or extending to base of first branched anal-fin ray in females). |
| Striking features | |
| Body shape lateral | elongated |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | terminal |
| Type of scales | cycloid scales |
| Diagnosis |
The unique color pattern of the body consisting of a black midlateral stripe which extends from the posterior margin of the eye to the median caudal-fin rays distinguishes Hemigrammus ataktos from all congeners which possess dark stripe or thin line extending approximately from the humeral blotch or from the vertical through dorsal-fin origin to the caudal fin. It differs also from all congeners, except H. filamentosus Zarske, by having elongated anteriormost portions of the dorsal, pelvic, and anal fins in mature males (Ref. 96858). Description: dorsal-fin rays ii,9-10; anal- fin rays iv-vi, 20-24; pectoral-fin rays i,10-12; pelvic-fin rays i,7 (Ref. 96858). |
| Ease of Identification |
| Lateral Lines | Interrupted: No |
| Scales on lateral line | 32 - 36 |
| Pored lateral line scales | |
| Scales in lateral series | |
| Scale rows above lateral line | 5 - 6 |
| Scale rows below lateral line | |
| Scales around caudal peduncle | 14 - 14 |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | 14 - 15 |
| total | 33 - 34 |
| Attributes | |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | 11 - 12 |
| Adipose fin | present |
| Attributes | forked |
| Fins number | |
| Spines total | |
| Soft-rays total |
| Pectoral | Attributes more or less normal |
| Spines | |
| Soft-rays 11 - 13 | |
| Pelvics | Attributes |
| Position abdominal before origin of D1 | |
| Spines | |
| Soft-rays 8 - 8 |