分類 / 名前
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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.
環境:環境 / 気候帯 / 深さの範囲 / 分布範囲
生態学
; 新鮮な水 底生の漂泳性. Tropical
South America: Amazon basin in Brazil and Peru.
サイズ / 重さ / 年齢
成熟: Lm ?  range ? - ? cm
Max length : 28.5 cm TL オス/雌雄の選別がない; (Ref. 55508); 最大公表体重: 65.00 g (Ref. 55508)
簡単な記述
検索表 | 形態学 | 形態計測学
背面の脊椎 (合計) : 0; 背鰭 (合計) : 0; 臀鰭: 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).
ライフサイクルと交尾行動
成熟 | 繁殖 | 放精 | 卵 | 生産力 | 幼生
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)
IUCNのレッドリストの状況は (Ref. 130435: Version 2025-2 (Global))
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インターネットの情報源
モデルに基づく推定値
系統多様性指数 (参照 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). |
栄養段階 (参照 69278) |
3.2 ±0.40 se; based on food items. |
回復力 (参照 120179) |
高い, 15か月以下の倍増期間の最小個体群 (Preliminary K or Fecundity.). |
漁業の脆弱性 (Ref. 59153) |
Low to moderate vulnerability (25 of 100). 🛈 |