| Main Ref. | Keith, P. and J. Allardi (coords.), 2001 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | elongated |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | scales embedded or partly/completely absent |
| Diagnosis |
Distinguished from all other freshwater fishes in Europe by the following unique characters: two pairs of mental barbels; and anal fin with 83-91½ rays. Differs further from the following combination of features: body naked; large, depressed head; dorsal fin with 2-4½ rays; caudal fin rounded or truncate; no adipose fin; and anal rays almost touching caudal (Ref. 59043). Caudal fin with 17 rays (Ref. 2196). |
| 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 | 1 |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 1 - 1 |
| Soft-rays total | 4 - 5 |
| Adipose fin | absent |
| Attributes | more or less truncate; more or less normal |
| Fins number | 1 |
| Spines total | 1 - 1 |
| Soft-rays total | 83 - 95 |
| Pectoral | Attributes more or less normal |
| Spines 1 | |
| Soft-rays 14 - 17 | |
| Pelvics | Attributes more or less normal |
| Position abdominal behind origin of D1 | |
| Spines 1 | |
| Soft-rays 11 - 12 |