分類 / Names
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Characiformes (Characins) >
Characidae (Characins; tetras) > Stethaprioninae
Etymology: Astyanax: The name of Astyanax, Hector´s son in the Greek mythology (Ref. 45335); courensis: Named for its type locality, rio dos Couros, an important tributary of rio Tocantinzinho, upper rio Tocantins basin; adjective..
Environment: milieu / climate zone / depth range / distribution range
生態学
; 新鮮な水 外洋の; 深さの範囲 ? - 2 m (Ref. 84461). Tropical; 14°S - 15°S, 47°W - 48°W
South America: known from the rio dos Couros basin, tributary of rio Tocantinzinho, upper rio Tocantins basin, Alto Paraíso de Goiás, Chapada dos Veadeiros, Goiás State, Brazil (Ref. 84461).
サイズ / 重さ / 年齢
Maturity: Lm ? range ? - ? cm
Max length : 7.2 cm SL オス/雌雄の選別がない; (Ref. 84461)
簡単な記述
検索表 | 形態学 | 形態計測学
Astyanax courensis belongs to the A. scabripinnis species complex and is distinguished from other species of this complex by the number of scale rows between lateral line and pelvic fin origin (3-4 vs. 5-6), except from A. brachypterygium, A. burgerai Zanata & Camelier, A. goyanensis, A. intermedius Eigenmann, A. jenynsii, A. microschemos, A. rivularis Lütken, A. totae, and A. varzeae. It differs from A. brachypterygium, A. goyanensis, and A. totae by head length (24.9-28.2% SL, mean = 26.6 vs. 27.8-33.2, mean = 29.9, 27.7-32.3, mean = 31.6, and 27.9-32.8, mean = 29.7, respectively), and by the number of humeral spots (1 vs. 2, except in A. totae, which has one). It differs from A. burgerai and A. intermedius by shape of the dentary teeth (abruptly decreasing in size after fourth tooth vs. teeth gradually decreasing in size posteriorly), and orbital diameter (24.9-31.9% HL, mean = 27.9 vs. 34.6-40.6, mean = 38.0, 32.5-47.8, mean = 39.0, respectively); from A. jenynsii by the number of branched anal-fin rays (15-17, mean = 15.8 vs. 13-15, mean =14) and upper jaw length (40.6-50.0% HL, mean = 44.9 vs. 35.9-39.5, mean = 37.4); from A. rivularis by body depth (27.4-33.1% SL, mean = 30.5 vs. 35.0-46.0, mean = 40.3), and by the number of humeral spots (1 vs. 2); from A. varzeae by the number of lateral line scales (35-36, mean = 35.4 vs. 37-42, mean = 39), caudal-peduncle length (13.6-16.9% SL, mean =15.2 vs. 10.5-13.9, mean = 12.4) and orbital diameter (24.9-31.9% HL, mean = 27.9 vs. 30.9-44.5, mean = 37.9). Furthermore, it differs from A. microschemos and A. totae by the number of maxillary teeth (1 vs. 2-3 and 2-5, respectively). Astyanax courensis differs from only sympatric Astyanax species, A. goyanensis, by the number of pelvic-fin rays (8 vs. 7), and number of maxillary teeth (1 vs. 2-5), and by prepectoral distance (23.7-27.8% SL, mean = 26.4 vs. 27.7-32.0, mean = 30.4) (Ref. 84461).
The collection locality is around 1135 m above sea level, rio dos Couros in that point has moderate riparian vegetation and it is typically between 10 and 15 m wide, and 1.5 m deep. Although presenting some rapids, the water is clear, the substrate has stones, rocks, and some stretches with mud. Most of the specimens were collected on the stretch downstream from the waterfall, a few specimens on the stretch upstream of waterfall. Only 4 species were collected syntopically with A. courensis: Characidium stigmosum,
C. aff. zebra, Gymnotocinclus anosteos and Trichomycterus sp. The stomach contents of five specimens consisted of Plecoptera, Trichoptera, Chironomidae (Diptera), authochthonous and allochthonous insects, and digested vegetal organic matter; these stomachs were partially full (Ref. 84461).
Life cycle and mating behavior
Maturities | 繁殖 | Spawnings | Egg(s) | Fecundities | 幼生
Bertaco, V.A., F.R. Carvalho and F.C. Jerep, 2010. Astyanax goyanensis (Miranda-Ribeiro, 1944), new combination and Astyanax courensis, new species (Ostariophysi: Characiformes): two Characidae from the upper rio Tocantins basin, Central Brazil. Neotrop. Ichthyol. 8(2):265-275. (Ref. 84461)
Human uses
用具
特記事項
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インターネットの情報源
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).
栄養段階 (Ref.
69278): 2.9 ±0.4 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref.
59153): Low vulnerability (10 of 100).
