| Main Ref. | Delapieve, M.L.S., P.A. Lehmann and R.E. Reis, 2017 |
| Appearance refers to | |
| Bones in OsteoBase |
| Specialized organs | |
| Different appearance | |
| Different colors | |
| Remarks | Males possess a conical urogenital papilla behind the anal tube; mature males also have a pelvic-fin contact organ, composed of a row of enlarged odontodes on the dorsal surface of the first, sometimes second, pelvic-fin branched 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 | bony plates or armour |
| Diagnosis |
Leptotocinclus ctenistus can be diagnosed from its only congener L. madeirae by the presence of median series of abdominal plates, arranged in one single row (vs. median series of abdominal plates absent); and having 3-6 lateral abdominal plates (vs. 1-2, but one specimen with 3). It further differs by having larger size of preanal plate (7.0-12.0% SL vs. 1.5-6.4% SL) (Ref. 116855). |
| 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 | |
| Vertebrae | |
| preanal | |
| total | 27 - 27 |
| Attributes | no striking attributes |
| Fins number | 1 |
| Finlets No. | Dorsal |
| Ventral | |
| Spines total | 1 - 1 |
| Soft-rays total | 7 - 7 |
| Adipose fin | absent |
| Attributes | forked |
| Fins number | |
| Spines total | |
| Soft-rays total | 6 - 6 |
| Pectoral | Attributes |
| Spines 1 | |
| Soft-rays 6 - 6 | |
| Pelvics | Attributes |
| Position abdominal | |
| Spines | |
| Soft-rays 6 - 6 |