| Main Ref. | Lima, F.C.T. and M.R. Britto, 2001 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks | Males with lanceolate genital papilla close to anus. Females with small rod-like genital papilla. |
| Striking features | |
| Body shape lateral | elongated |
| Cross section | oval |
| Dorsal head profile | clearly convex |
| Type of eyes | more or less normal |
| Type of mouth/snout | |
| Position of mouth | sub-terminal/inferior |
| Type of scales | |
| Diagnosis |
Infraorbitals, preopercle and reduced nuchal plate covered by thick skin and not visible externally. Lateral line absent posterior to 2 small lateral line ossicles. Two pairs of maxillary barbels and a pair of mental barbels. Adipose fin preceded by a small, curved, well-ossified spine. |
| 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 |
| Ventral | |
| Spines total | 1 - 1 |
| Soft-rays total | 7 - 7 |
| Adipose fin | present |
| Attributes | more or less truncate; more or less normal |
| Fins number | |
| Spines total | 2 - 2 |
| Soft-rays total | 6 - 6 |
| Pectoral | Attributes more or less normal |
| Spines 1 | |
| Soft-rays 9 - 9 | |
| Pelvics | Attributes more or less normal |
| Position abdominal behind origin of D1 | |
| Spines 1 | |
| Soft-rays 6 - 6 |