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Gymnotiformes (Knifefishes) >
Gymnotidae (Naked-back knifefishes) > Gymnotinae
Etymology: Gymnotus: Greek, gymnos = naked (Ref. 45335); varzea: Named for the whitewater várzea floodplain, which this species is restricted to.
Environnement : milieu / zone climatique / profondeur / gamme de distribution
Écologie
; eau douce benthopélagique. Tropical
South America: Amazon basin in Brazil and Peru.
Taille / Poids / Âge
Maturité: Lm ?  range ? - ? cm
Max length : 28.5 cm TL mâle / non sexé; (Ref. 55508); poids max. publié: 65.00 g (Ref. 55508)
Description synthétique
Clés d'identification | Morphologie | Morphométrie
Épines dorsales (Total) : 0; Rayons mous dorsaux (Total) : 0; Rayons mous anaux: 230 - 310. Distinguished from its congeners endemic to the Amazon and Orinoco Basins and the Guyana Shield in having a color pattern of 16-22 oblique dark pigment bands with wavy and irregular margins in which the majority of bands at midbody form X-shaped patterns (resembling metaphase chromosomes) and in which the dark bands are about twice as broad as the pale interbands. Further differs from its congeners in having the following unique combination of characters: clear (unpigmented) patch at the caudal end of the anal-fin membrane in specimens 6.0-23.7 cm; and bands never divided to form band pairs (Ref. 55508).
Facultative air-breathing in the genus (Ref. 126274); Found in root mats of floating meadows in floodplains (Ref. 55508). Gulps atmospheric air into the hypervascularized posterior chamber of its gas bladder (Ref. 55508). Feeds on small aquatic invertebrates such as chironomid larvae, insect nymphs and microcrustaceans (Ref. 55508).
Cycle de vie et comportement reproducteur
Maturité | Reproduction | Frai | Œufs | Fécondité | Larves
Crampton, W.G.R., D.H. Thorsen and J.S. Albert, 2005. Three new species from a diverse, sympatric assemblage of the electric fish Gymnotus (Gymnotiformes: Gymnotidae) in the lowland Amazon basin, with notes on ecology. Copeia 2005(1):82-99. (Ref. 55508)
Statut dans la liste rouge de l'IUCN (Ref. 130435: Version 2025-2 (Global))
Menace pour l'homme
Harmless
Utilisations par l'homme
Outils
Articles particuliers
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Sources Internet
Estimations basées sur des modèles
Indice de diversité phylogénétique (Réf. 82804) |
PD50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high]. |
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Bayesian length-weight
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a=0.00427 (0.00202 - 0.00902), b=2.98 (2.79 - 3.17), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245). |
Niveau trophique (Réf. 69278) |
3.2 ±0.40 se; based on food items. |
Résilience (Réf. 120179) |
Haut, temps minimum de doublement de population inférieur à 15 mois (Preliminary K or Fecundity.). |
Vulnérabilité de la pêche (Ref. 59153) |
Low to moderate vulnerability (25 of 100). 🛈 |