Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Actinopterygii (ray-finned fishes) > Characiformes
(Characins) > Characidae
(Characins) > Stevardiinae
Etymology: Xenurobrycon: Greek, xenos = strange + Greek ,oura = tail + Greek, bryx, brykos = to bite (Ref. 45335); varii: Named for Richard P. Vari, an esteemed person and ichthyologist, for his contributions to the systematics of fishes and his continuous support and aid to the authors.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical
South America: Rio Tapajós and rio Jamanxim in Pará, Brazil.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 1.4 cm SL male/unsexed; (Ref. 109914)
Morphology | Morphometrics
soft rays: 16 - 20. Xenurobrycon varii can be easily distinguished from its congeners by the dark posterior half of both caudal-fin lobes (vs. hyaline) and the lack of infraorbitals 4 and 5 (vs. absence of infraobitals 1, 4 and 5 in X. coracoralinae and presence of infraorbitals 1-5 in X. heterodon, X. macropus, X. polyancistrus and X. pteropus). It further differs from other species of Xenurobrycon , except X. coracoralinae and X. macropus, by having a set of lamellar processes on the eighth principal ray of the lower caudal-fin lobe (vs. absence in X. heterodon, X. polyancistrus and X. pteropus). It can be diagnosed from X. coracoralinae by having hooks on the last unbranched plus the first 9th-12th branched anal-fin rays of mature males (vs. hooks present only on last unbranched and first 4th-5th branched rays). In addition, it can be distinguished from X. heterodon by having only conical dentary teeth (vs. anterior dentary teeth tricuspid). It differs also from X. polyancistrus by the posterior anal-fin hooks approximately equal or reduced in size posteriorly in mature males (vs. posterior larger anal-fin hooks). It can be further differentiated from X. pteropus by the absence of adipose-fin (vs. presence) and by having 15-18 predorsal scales (vs. 13) (Ref. 109914).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Mendonça, M.B., L.A.W. Peixoto, G.M. Dutra and A.L. Netto-Ferreira, 2016. A new miniature of Xenurobryconini (Characiformes: Characidae) from the rio Tapajós basin, Brazil. Neotrop. Ichthyol. 14(1):1-8. (Ref. 109914)
IUCN Red List Status (Ref. 115185)
CITES (Ref. 115941)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5156 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01175 (0.00541 - 0.02553), b=2.98 (2.78 - 3.18), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.0 ±0.4 se; Based on size and trophs of closest relatives
Resilience (Ref. 69278
Vulnerability (Ref. 59153
): Low vulnerability (10 of 100) .