| Main Ref. | Schmitter-Soto, J.J., 2017 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks |
| Striking features | |
| Body shape lateral | fusiform / normal |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | |
| Diagnosis |
Astyanax bacalarensis is distinguished from its congeners in the Yucatan by the following characters: anal fin origin never overlapping last dorsal-fin ray (always overlapping in A. altior); head length 28% SL or less (27% or more in A. altior); predorsal length, mean 50.4% SL (mean 53% or more in A. altior and A. angustifrons); mean distance between origins of pelvic and anal fins, 20.5% SL (vs. mean 19.3% or less); humeral spot rectangular-triangular to oval (P-shaped to indistinct in A. belizianus and A. brevimanus) (Ref. 118583). |
| Ease of Identification |
| Lateral Lines | Interrupted: No |
| Scales on lateral line | 32 - 38 |
| Pored lateral line scales | |
| Scales in lateral series | |
| Scale rows above lateral line | 6.5 - 8 |
| Scale rows below lateral line | |
| Scales around caudal peduncle | 14 |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | 11 - 14 |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | |
| total | 32 - 33 |
| Attributes | no striking attributes |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | 9 - 11 |
| Adipose fin |
| Attributes | forked |
| Fins number | |
| Spines total | |
| Soft-rays total | 21 - 27 |
| Pectoral | Attributes more or less normal |
| Spines | |
| Soft-rays 10 - 11 | |
| Pelvics | Attributes more or less normal |
| Position abdominal | |
| Spines | |
| Soft-rays |