| Main Ref. | Nakamura, I., 1985 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | no special organs |
| Different appearance | males alike females |
| Different colors | |
| Remarks |
| Striking features | striking type of mouth |
| Body shape lateral | elongated |
| Cross section | |
| Dorsal head profile | clearly concave |
| Type of eyes | more or less normal |
| Type of mouth/snout | more or less normal |
| Position of mouth | sub-terminal/inferior |
| Diagnosis |
Body elongate and compressed; upper jaw prolonged into a very long beak; two dorsal fins, the first very large and tail; pelvic fins narrow but very long, almost reaching anus, with 1 spine and 2 rays; body covered with small, embedded scales with 1 or 2 blunt points; back dark with about 20 bluish vertical bars; belly pale silver; membrane of first dorsal fin blue black with numerous dark spots (Ref. 55763). A slender billfish with a high, sail-like first dorsal fin (Ref. 26938). |
| Ease of Identification |
| Lateral Lines | 1 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 | 0 |
| Gill clefts (sharks/rays only) | absent |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | |
| total |
| Attributes | extending over most of the back length |
| Fins number | 2 |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 0 - 0 |
| Soft-rays total | 47 - 53 |
| Adipose fin | absent |
| Attributes | forked; more or less normal |
| Fins number | 2 |
| Spines total | 2 - 2 |
| Soft-rays total | 12 - 15 |
| Pectoral | Attributes more or less normal |
| Spines 0 | |
| Soft-rays 18 - 20 | |
| Pelvics | Attributes largely reduced to one ray |
| Position thoracic beneath origin of D1 | |
| Spines 0 | |
| Soft-rays 1 |