Astyanax douradilho Bertaco, 2014

Family:  Characidae (Characins; tetras), subfamily: Stethaprioninae
Max. size:  9 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; pH range: 6.5 - 6.8
Distribution:  South America: Rio Maquiné, rio Tramandaí system in Brazil.
Diagnosis:  Dorsal soft rays (total): 10-11; Vertebrae: 36-37. Astyanax douradilho is distinguished from all congeners from the rio Uruguay basin, laguna dos Patos and rio Tramandaí systems by having 3-5 maxillary tricuspid teeth ( except A. henseli, A. laticeps, and A. paris), and by the absence of a conspicuous dark stripe from humeral region to caudal peduncle. It differs from A. henseli by having 11-12 gill rakers on lower branch of first arch (vs. 15-19), from A. laticeps by having two vertically elongated humeral spots (vs. one oval horizontally elongate), and from A. paris by having 37-39 perforated scales along the lateral line (vs. 34-36). It differs from all congeners by the following combination of characters: presence of two vertically elongate humeral spots, a conspicuous caudal spot; absence of a conspicuous dark stripe from humeral region to caudal peduncle; 3-5 maxillary tricuspid teeth; 22-24 branched anal-fin rays; 37-39 perforated scales along the lateral line; head length (26.0-29.9% SL); upper jaw length (43.8-50.6% HL); and snout length (23.0-28.6% HL) (Ref. 96006). Description: Anal-fin rays iii, or iv, 22, 23, or 24 (Ref. 96006).
Biology:  Found in relatively small, clear water streams up to 1 m deep, with stones and rocks on bottom, and moderate riparian vegetation. Collected at around 300 m above sea level. Based on examination of several lots in fish collection, this species seems to occur only in mainstream of small rivers draining from Serra Geral formation, and was not found in the other subregion basin formed by lagoons of the Coastal Plain according to Malabarba & Isaia in 1992 (Ref. 96006).
IUCN Red List Status: Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
Threat to humans:  harmless


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