| Main Ref. | Hart, J.L., 1973 |
| 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 |
No true fins - one dorsal finfold, far back, median, very low, continuous with caudal; caudal broad, rounded; ventral finfold very low, origin somewhat posterior to last gill pore, extending to anus (Ref. 6885). Dark brown, tan, gray, or brownish red, often tinted with blue or purple, never black, lighter ventrally, rarely with large patches of white; preserved specimens light brown (Ref. 6885). |
| 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 |
| Attributes | |
| Fins number | |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 0 - 0 |
| Soft-rays total | 0 - 0 |
| Adipose fin | absent |
| Attributes | other (see remark) |
| Fins number | |
| Spines total | 0 - 0 |
| Soft-rays total | 0 - 0 |
| Pectoral | Attributes absent |
| Spines 0 | |
| Soft-rays 0 - 0 | |
| Pelvics | Attributes suppressed/absent |
| Position | |
| Spines 0 | |
| Soft-rays 0 - 0 |