| Main Ref. | Romero, A. and P.B.S. Vanselow, 2000 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | eel-like |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | |
| Diagnosis |
Body extremely elongated, eel-like and roundish. No fins except a thin rayless finfold near and around the tip of the tail. No externally visible eyes. The lateral line system is distinct and continues to near the tip of the tail. Anus in anterior half of the body. Whitish coloration in the skin. |
| Ease of Identification |
| Lateral Lines | 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 | |
| Vertebrae | |
| preanal | |
| total | 150 |
| Attributes | |
| Fins number | |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | |
| Adipose fin | absent |
| Attributes | other (see remark); confluent |
| Fins number | |
| Spines total | |
| Soft-rays total |
| Pectoral | Attributes absent |
| Spines | |
| Soft-rays | |
| Pelvics | Attributes suppressed/absent |
| Position | |
| Spines | |
| Soft-rays |