| Main Ref. | Keith, P. and F.J. Meunier, 2000 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | no special organs |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | long whip-like tail |
| Body shape lateral | elongated |
| Cross section | compressed |
| Dorsal head profile | more or less straight |
| Type of eyes | more or less normal |
| Type of mouth/snout | more or less normal |
| Position of mouth | terminal |
| Type of scales | |
| Diagnosis |
dorsal, caudal and pelvic fins absent; 0-4 electrocytes rows, eye diameter 16.3 to 22.9 times in head length; body color grey, slightly translucent, with a darker dorsum and hyaline fins. |
| Ease of Identification | likely to be confused with closely related species. |
| Lateral Lines | 1 Interrupted: No |
| Scales on lateral line | |
| Pored lateral line scales | |
| Scales in lateral series | |
| Scale rows above lateral line | |
| Scale rows below lateral line | |
| Scales around caudal peduncle | |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | 13 - 15 |
| Vertebrae | |
| preanal | |
| total | 72 - 86 |
| Attributes | greatly reduced or absent |
| Fins number | |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | |
| Adipose fin | absent |
| Attributes | other (see remark) |
| Fins number | 1 |
| Spines total | |
| Soft-rays total | 165 - 190 |
| Pectoral | Attributes more or less normal |
| Spines | |
| Soft-rays 16 - 16 | |
| Pelvics | Attributes suppressed/absent |
| Position | |
| Spines | |
| Soft-rays |