Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Characiformes (Characins) >
Acestrorhamphidae (American tetras) > Acestrorhamphinae
Etymology: Psalidodon: Greek, psalis, -idos = scissors + Greek, odous = teeth (Ref. 45335); dissensus: Name from Latin dissensus, meaning disagreement, in reference to the larger maxillary heptacuspid tooth peculiar to the species and unusual in Astyanax species.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Subtropical
South America: Laguna dos Patos system and rio Uruguay drainage; one specimen from coastal lagoon of rio Tramandaí system.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 12.4 cm TL male/unsexed; (Ref. 125973); max. published weight: 21.30 g (Ref. 126299)
Short description
Identification keys | Morphology | Morphometrics
Dorsal soft rays (total): 10 - 11; Anal soft rays: 27 - 33; Vertebrae: 35 - 36. 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).
Body shape (shape guide): fusiform / normal.
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Terán, G.E., M.F. Benitez and J.M. Mirande, 2020. Opening the Trojan house: phylogeny of Astyanax, two genera and resurrection of Psalidodon (Teleostei: Characidae). Zool. J. Lin. Soc. 190(4):1217-1234. (Ref. 123753)
IUCN Red List Status (Ref. 130435: Version 2025-2)
Threat to humans
Harmless
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