| Main Ref. | Anderson, M.E. and A.A. Balanov, 2000 |
| Appearance refers to | Male; Female |
| Bones in OsteoBase |
| Specialized organs | no special organs |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | none |
| Body shape lateral | eel-like |
| Cross section | circular |
| 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 |
Distinguished from congeners with the following combination of characters: pelvic fins and pyloric caeca absent; vertebrae 28-31 + 103-110; dorsal fin origin associated with vertebrae 2-3; postorbital pores five (rarely four or six); occipital and interorbital pores present; pseudobranch filaments 5-10; vomerine and palatine teeth present; lateral line ventral, complete. |
| Ease of Identification | easy to distinguish from other 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 | |
| Vertebrae | |
| preanal | 28 - 31 |
| total | 132 - 139 |
| Attributes | extending over most of the back length |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | 0 - 0 |
| Soft-rays total | 128 - 134 |
| Adipose fin | absent |
| Attributes | pointed; confluent |
| Fins number | 1 |
| Spines total | 0 - 0 |
| Soft-rays total | 107 - 115 |
| Pectoral | Attributes more or less normal |
| Spines 0 | |
| Soft-rays 13 - 17 | |
| Pelvics | Attributes suppressed/absent |
| Position | |
| Spines | |
| Soft-rays |