| Main Ref. | Costa, W.J.E.M., 2002 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | elongated |
| Cross section | oval |
| Dorsal head profile | more or less straight |
| Type of eyes | more or less normal |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | |
| Diagnosis |
Possess an asymmetrical caudal fin, with convex dorsal outline and a straight ventral outline, anteriormost ventral procurrent ray; a white stripe with narrow ventral black border on the ventral edge of the caudal fin of male. Dorsal fin of male approximately triangular, tip pointed ending in 2 short filamentous rays with the tips reaching middle of caudal fin; dorsal fin rounded to slightly pointed in female. Anal fin of male approximately rectangular, posterior tip slightly elongated; rounded in female. |
| Ease of Identification |
| Lateral Lines | Interrupted: No |
| Scales on lateral line | 27 - 28 |
| Pored lateral line scales | |
| Scales in lateral series | |
| Scale rows above lateral line | |
| Scale rows below lateral line | |
| Scales around caudal peduncle | 12 - 12 |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | 7 - 8 |
| on upper limb | 2 - 2 |
| total | |
| Vertebrae | |
| preanal | |
| total | 28 - 29 |
| Attributes | last fin rays very elongated |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | 15 - 17 |
| Adipose fin | absent |
| Attributes | other (see remark); asymmetric |
| Fins number | 1 |
| Spines total | |
| Soft-rays total | 18 - 21 |
| Pectoral | Attributes rays very elongated |
| Spines | |
| Soft-rays 13 - 14 | |
| Pelvics | Attributes more or less normal |
| Position abdominal before origin of D1 | |
| Spines | |
| Soft-rays 6 - 6 |