| Main Ref. | Muus, B.J. and J.G. Nielsen, 1999 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | other |
| Different appearance | always different morphology between mature adults |
| Different colors | |
| Remarks | Males with brood pouch; females with ovipositor (Ref. 205). |
| Striking features | |
| Body shape lateral | eel-like |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | tube-like |
| Position of mouth | terminal |
| Type of scales | |
| Diagnosis |
Snout is compressed and taller than the eye diameter (Ref. 35388) and anterior trunk rings not fused ventrally (Ref. 59043). |
| 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 | |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | |
| Adipose fin |
| Attributes | more or less truncate |
| Fins number | |
| Spines total | |
| Soft-rays total |
| Pectoral | Attributes more or less normal |
| Spines | |
| Soft-rays | |
| Pelvics | Attributes suppressed/absent |
| Position absent | |
| Spines | |
| Soft-rays |