| Main Ref. | Crampton, W.G.R., K.G. Hulen and J.S. Albert, 2004 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | |
| Cross section | |
| Dorsal head profile | clearly convex |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | sub-terminal/inferior |
| Type of scales | cycloid scales |
| Diagnosis |
Body and head of living specimens uniformly black or very dark purple-brown with no humeral spot or patch; juveniles undergo striking pigmentation change from uniformly black by day to very pale with two distinct vertical saddle-like markings at night; dorsal margin of head well rounded (very convex) in adults (Ref. 52797). Description: Caudal fin absent. |
| Ease of Identification |
| Lateral Lines | Interrupted: No |
| Scales on lateral line | 190 - 280 |
| Pored lateral line scales | |
| Scales in lateral series | |
| Scale rows above lateral line | 15 - 21 |
| Scale rows below lateral line | 7 - 13 |
| Scales around caudal peduncle | |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | 22 - 26 |
| total |
| Attributes | greatly reduced or absent |
| Fins number | |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | 0 - 0 |
| Soft-rays total | 0 - 0 |
| Adipose fin |
| Attributes | other (see remark) |
| Fins number | |
| Spines total | |
| Soft-rays total | 195 - 312 |
| Pectoral | Attributes |
| Spines | |
| Soft-rays 15 - 17 | |
| Pelvics | Attributes suppressed/absent |
| Position absent | |
| Spines 0 | |
| Soft-rays 0 - 0 |