Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Actinopterygii (ray-finned fishes) > Characiformes
(Characins) > Crenuchidae
(South American darters) > Characidiinae
Etymology: Characidium: Diminutive of Charax, -akos = a fish without identification (Ref. 45335); satoi: Named for Dr. Yoshimi Sato, a biologist of the Companhia de Desenvolvivmento dos Vales do São Francisco e do Parnaíba (CODEVASF), for his contributions to the knowledge and conservation of the ichthyofauna of the Rio São Francisco drainage.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical
South America: Rio São Francisco basin, Brazil.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 4.4 cm SL male/unsexed; (Ref. 104008)
Morphology | Morphometrics
soft rays: 8;
Vertebrae: 34. Characidium satoi is distinguished externally from its congeners by having area between pelvic fin and origin of anal fin moderate to strongly convex in lateral view (vs. area between the pelvic fin and the anal-fin origin straight); and by color pattern, with females, juveniles, and non-breeding males consisting of irregular and discontinuous bars, forming dorsal blotches separated from ventral part, which is V-shaped, W-shaped, or diamond-shaped, or breeding males having less distinct patterning and an overall darker, more uniform pigmentation. It possesses one putative internal autapomorphy, the anteriormost first anal-fin radials inserted between the fifth and sixth caudal vertebrae. Additional external diagnostic characters useful for its identification include the following: isthmus scaled; lateral line complete, with 34-37 perforated scales; anal-fin origin far posterior from anus, separated by 4 to 7 scales (vs. anal-fin origin close to anus, separated from anus by 2 to 4 scales in all congeners, except in C. hasemani, C. litorale , and C. zebra ); distal tip of anal-fin rays reaching base of ventral caudal-fin ray (vs. not reaching, except in C. bahiense, C. hasemani, C. mirim, and C. zebra, and mature males of C. rachovii); and presence of hooks on the pectoral- and pelvic-fin rays in males (vs. absence, except in C. bahiense, C. bimaculatum, C. lagosantense, C. litorale, C. mirim, C. nupelia, C. stigmosum, C. xanthopterum, and C. xavante) (Ref. 104008).
Found only in a single locality characterized by fast flowing waters with periodic shallow riffles no more than 0.4 m deep alternating with artificial pools more than 2 m deep. Occurs only in the rapids (Ref. 104008).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Melo, M.R.S. and O.T. Oyakawa, 2015. A new species of Characidium Reinhardt (Characiformes: Crenuchidae) with a distinctively dimorphic male. Copeia 103(2):281-289. (Ref. 104008)
IUCN Red List Status (Ref. 120744)
CITES (Ref. 118484)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01122 (0.00514 - 0.02450), b=3.04 (2.87 - 3.21), in cm Total Length, based on all LWR estimates for this body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.4 ±0.3 se; Based on size and trophs of closest relatives
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .