| Main Ref. | Nakamura, I., T. Inada, M. Takeda and H. Hatanaka, 1986 |
| Appearance refers to | |
| Bones in OsteoBase | Skull, Spine |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | striking shape of body |
| Body shape lateral | fusiform / normal |
| Cross section | oval |
| Dorsal head profile | more or less straight |
| Type of eyes | more or less normal |
| Type of mouth/snout | more or less normal |
| Position of mouth | superior |
| Type of scales | |
| Diagnosis |
Caudal fin margin usually concave. Color is silvery on back, silvery whitish on belly. M. gayi gayi and M. gayi peruanus differ by the total number of vertebrae, total number of gill rakers and relative length of head (Ref. 1371). |
| Ease of Identification |
| Lateral Lines | 1 Interrupted: No |
| Scales on lateral line | 106 - 130 |
| 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) | |
| Gill rakers | |
| on lower limb | 15 - 19 |
| on upper limb | 3 - 6 |
| total | 19 - 25 |
| Vertebrae | |
| preanal | |
| total | 49 - 53 |
| Attributes | no striking attributes |
| Fins number | 2 |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 1 - 1 |
| Soft-rays total | 45 - 54 |
| Adipose fin | absent |
| Attributes | other (see remark); more or less normal |
| Fins number | 1 |
| Spines total | 0 - 0 |
| Soft-rays total | 36 - 42 |
| Pectoral | Attributes more or less normal |
| Spines 0 | |
| Soft-rays 15 - 17 | |
| Pelvics | Attributes more or less normal |
| Position thoracic before origin of D1 | |
| Spines 0 | |
| Soft-rays 7 - 7 |