Morphology Data of Astyanax dissensus
Identification keys
Main Ref. De Lucena, C.A.S., J.B. Castro and V.A. Bertaco, 2013
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth terminal
Type of scales

This species can be diagnosed from all congeners in the rio Uruguay basin, laguna dos Patos and rio Tramandaí systems, except Astyanax ojiara, by the presence of one heptacuspid tooth on maxillary (vs. tri- to pentacuspid teeth). It differs from other congeners, including species complex A. bimaculatus and A. scabripinnis by the following combination of characters: two humeral spots, the first spot vertically elongate; conspicuous caudal spot; 35-39 perforated lateral line scales; 6-7 scale rows between dorsal-fin origin and lateral line; 22-28 branched anal-fin rays; predorsal region scaled; one heptacuspid maxillary tooth; body depth 37.2-44.2% of SL; and head length 22.7-27.3% of SL). It is distinguished from A. ojiara by the head length 22.7- 27.3% (vs. 27.3-29.5% of SL) and by the presence of hooks on anal fin on males (vs. all fins with hooks) (Ref. 94153).

Ease of Identification

Meristic characteristics of Astyanax dissensus

Lateral Lines Interrupted: No
Scales on lateral line 35 - 39
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line 6 - 7
Scale rows below lateral line
Scales around caudal peduncle 14 - 17
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 10 - 13
on upper limb 6 - 8
total 16 - 21
preanal 15 - 16
total 35 - 36


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total
Soft-rays total 10 - 11
Adipose fin present

Caudal fin

Attributes forked

Anal fin(s)

Fins number
Spines total
Soft-rays total 27 - 33

Paired fins

Pectoral Attributes  more or less normal
Soft-rays   12 - 14
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Soft-rays   7 - 8
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Torres, Armi G.
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