| Main Ref. | Nakamura, I. and N.V. Parin, 1993 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | striking shape of body |
| Body shape lateral | eel-like |
| 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 | superior |
| Type of scales | scales embedded or partly/completely absent |
| Diagnosis |
Pelvic fins represented by a single spine in juveniles, inserted before the base of the pectoral fins, but entirely absent in adults. Body color is coppery black with iridescent tint. The inside of the mouth and gill cavities black. |
| Ease of Identification |
| 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 | 0 |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | |
| total | 111 - 117 |
| Attributes | extending over most of the back length |
| Fins number | 1notched No |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 42 - 45 |
| Soft-rays total | 61 - 66 |
| Adipose fin | absent |
| Attributes | forked; more or less normal |
| Fins number | 1 |
| Spines total | 2 - 2 |
| Soft-rays total | 51 - 57 |
| Pectoral | Attributes more or less normal |
| Spines | |
| Soft-rays | |
| Pelvics | Attributes other (see diagnosis) |
| Position thoracic beneath origin of D1 | |
| Spines 1 | |
| Soft-rays 0 - 0 |