| Main Ref. | Compagno, L.J.V., 1984 |
| 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 |
Black or blackish brown in color, dorsal fins with very small fin spines, very long snout, greatly elongated labial furrows that nearly encircle mouth, lanceolate upper teeth and bladelike lower teeth with moderately long, oblique cusps, fairly slender body that does not taper abruptly from pectoral region, moderately large lateral trunk denticles with partly smooth, oval, cuspidate crowns in adults and subadults (Ref. 247). |
| 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 | 2 - 2 |
| Soft-rays total | 0 - 0 |
| Adipose fin | absent |
| Attributes | other (see remark); asymmetric |
| Fins number | |
| 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 behind origin of D1 | |
| Spines 0 | |
| Soft-rays 0 - 0 |