| Main Ref. | Nielsen, J.G. and S. Ohashi, 2011 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | |
| Diagnosis |
Penopus microphthalmus differs from P. japonicus by the following characters: has a higher number of dorsal, 135-158 (vs. 117) and anal, 106-122 (vs. 89) fin rays; lower number of preopercular spines, 4-7 (vs. 9); indistinct spine behind the posterior nostril (vs. distinct, 1% SL); by the bigger horizontal diameter of the eye 1.1-1.6% SL (vs. 0.8); and in having an almost fully scaled head (vs. squamation of the head restricted to the middle part of the preopercle) (Ref. 87601). |
| 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 | 16 - 24 |
| Vertebrae | |
| preanal | 18 - 19 |
| total | 77 - 83 |
| Attributes | |
| Fins number | 1 |
| Finlets No. | Dorsal 0 - 0 |
| Ventral 0 - 0 | |
| Spines total | 0 - 0 |
| Soft-rays total | 135 - 158 |
| Adipose fin | absent |
| Attributes |
| Fins number | 1 |
| Spines total | 0 - 0 |
| Soft-rays total | 106 - 122 |
| Pectoral | Attributes |
| Spines 0 | |
| Soft-rays 18 - 19 | |
| Pelvics | Attributes |
| Position | |
| Spines 0 | |
| Soft-rays 1 - 1 |