Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Gymnotiformes (Knifefishes) >
Gymnotidae (Naked-back knifefishes) > Gymnotinae
Etymology: Gymnotus: Greek, gymnos = naked (Ref. 45335); chimarrao: Named for chimarrão, the traditional mate tea (Ilex paraguariensis) of Rio Grande do Sul, Brazil and neighboring counties.
State, Brazil..
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic. Tropical
South America: Arroio Grande in the Rio Taquari drainage, Brazil.
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 24.3 cm TL male/unsexed; (Ref. 118108)
Short description
Identification keys | Morphology | Morphometrics
Anal soft rays: 180 - 213. Distinguished from all 32 congeners except for some specimens (over 30.0 cm) of Gymnotus ardilai from the Río Magdalena drainage in northwest South America in having a pigmentation pattern in which the oblique dark-pigmented bands are faint, and difficult to distinguish from the ground color. Diagnosed from Gymnotus ardilai in having a shallower body depth (7.4-9.1 % TL [mean 8.2] vs. 11.4-13.2 [12.3]). Differs also from all species in the Gymnotus pantherinus species-group (and is placed in the Gymnotus carapo species-group) by the presence of two (vs. one) laterosensory canal pores in the preopercular-mandibular series of the dorsoposterior portion of the preopercle. Can be differentiated from all species in the Gymnotus carapo species-group that occur south of the Amazon basin except Gymnotus inaequilabiatus in having a much shallower body depth (7.4-9.1 % TL [mean 8.2] vs. 8.9-11.6 [mean 11.1] in Gymnotus bahianus, 9.8-10.3 [mean 10.1] in Gymnotus paraguensis, and 10.3-13.1 [mean 11.7] in Gymnotus sylvius). Differs further from Gymnotus inaequilabiatus in possessing a substantially narrower head (53.1-59.3 % HL [mean 57.5] vs. 65.3- 72.0 [mean 67.8]) (Ref. 75065).
Facultative air-breathing in the genus (Ref. 126274); This species is known from a small stream, 1.5 m width, running through gallery forest in low hills, with altitude 54 m above mean sea level; substrate is mud and sand. All captured specimens were from marginal grasses rooted to the bottom of the stream in areas sheltered from the stream flow (with negligible current); dark-stained water; conductivity 107 μS·cm-1, temperature 24.1 °C (Ref. 75065)
Life cycle and mating behavior
Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae
Cognato, D., M.M. Richer-de-Forges, J.S. Albert and W.G.R. Crampton, 2007. Gymnotus chimarrao, a new species of electric fish (Gymnotiformes: Gymnotidae) from southern Brazil. Ichthyol. Explor. Freshwat. 18(4):375-382. (Ref. 75065)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01000 (0.00244 - 0.04107), b=3.04 (2.81 - 3.27), in cm total length, based on all LWR estimates for this body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.3 ±0.4 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Low vulnerability (14 of 100).
