| Main Ref. | Malabarba, L.R. and F.C. Jerep, 2014 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks | Sexually mature males possess hooks on pelvic- and anal-fin rays, ventrally arched caudal peduncle in preserved specimens; hypertrophied hook bearing anal-fin rays, expanded in sagittal plane usually with fused ray segments; and hypertrophied ventral procurrent caudal-fin rays. |
| Striking features | |
| Body shape lateral | elongated |
| Cross section | |
| Dorsal head profile | |
| Type of eyes | |
| Type of mouth/snout | |
| Position of mouth | |
| Type of scales | cycloid scales |
| Diagnosis |
Serrapinnus aster can be distinguished from all congeners except S. potiguar, by having scimitar-shaped ventral procurrent caudal-fin rays in mature males, almost all of which form a semicircle, resulting in a portion of the ventral procurrent caudal-fin rays having a multi-pointed partial star-shaped margin (vs. ventral procurrent caudal-fin rays rod-shaped or spatulate, usually parallel to each other, except for the anteriormost procurrent rays being inclined forward in some species). It differs from S. potiguar and congeners by having 7-9 cusps on the premaxillary teeth (vs. 5 cusps in S. microdon and S. potiguar, 9 -11 in S. lucindai, S. sterbai and S. tocantinensis and 10-12 in S. gracilis and S. littoris), incomplete lateral line (vs. complete in S. heterodon), dorsal fin hyaline (vs. with a proximal black blotch in S. notomelas), and the absence of a black spot on the posteroventral region of the abdomen (vs. presence in S. kriegi) (Ref. 96959). |
| Ease of Identification |
| Lateral Lines | Interrupted: No |
| Scales on lateral line | 31 - 35 |
| Pored lateral line scales | 6 - 13 |
| Scales in lateral series | |
| Scale rows above lateral line | 5 - 6 |
| Scale rows below lateral line | |
| Scales around caudal peduncle | 12 - 14 |
| Barbels | |
| Gill clefts (sharks/rays only) | |
| Gill rakers | |
| on lower limb | |
| on upper limb | |
| total | |
| Vertebrae | |
| preanal | 15 - 15 |
| total |
| Attributes | no striking attributes |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | |
| Soft-rays total | 10 - 11 |
| Adipose fin | present |
| Attributes | forked |
| Fins number | |
| Spines total | |
| Soft-rays total | 19 - 22 |
| Pectoral | Attributes |
| Spines | |
| Soft-rays 10 - 12 | |
| Pelvics | Attributes |
| Position abdominal before origin of D1 | |
| Spines | |
| Soft-rays 8 - 8 |