| Main Ref. | Compagno, L.J.V., 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 | placoid scales |
| Diagnosis |
Mouth well in front of eyes; spineless dorsal fins far posterior on tail; greatly elongated thick precaudal tail, long and low anal fin just anterior to caudal fin, prominent predorsal and interdorsal ridges on back, dorsal fins with nearly straight posterior margins, first dorsal-fin origin opposite or just behind pelvic fin insertions, second dorsal fin usually with a longer base than first; no color pattern (Ref. 43278). |
| 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 | 2 |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 0 - 0 |
| Soft-rays total | 0 - 0 |
| Adipose fin | absent |
| Attributes | heterocercal |
| Fins number | 1 |
| Spines total | 0 - 0 |
| Soft-rays total | 0 - 0 |
| Pectoral | Attributes more or less normal |
| Spines 0 | |
| Soft-rays 0 - 0 | |
| Pelvics | Attributes more or less normal |
| Position abdominal before origin of D1 | |
| Spines 0 | |
| Soft-rays 0 - 0 |