Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Teleostei (teleosts) >
Characiformes (Characins) >
Characidae (Characins; tetras) > Stevardiinae
Etymology: Hemibrycon: Greek, hemi = half + Greek, bryko = to bite (Ref. 45335); sanjuanensis: Named for the San Juan River Basin, where the type series was collected.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic; pH range: 6.3 - 7.7; depth range 0 - 3 m (Ref. 98056). Tropical; 17°C - 22°C (Ref. 98056)
South America: upper San Juan River Basin, Tatamá River drainage in Colombia.
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 8.5 cm SL male/unsexed; (Ref. 98056)
Short description
Identification keys | Morphology | Morphometrics
Dorsal soft rays (total): 10 - 11; Vertebrae: 39 - 41. Hemibrycon sanjuanensis can be distinguished from H. boquiae, H. brevispini, H. cairoense, H. colombianus, H. mikrostiktos, H. metae, H. palomae, H. rafaelense and H. tridens by having a circular or oblong humeral spot located two scales posterior to the opercle (vs. 3-4 scales in H. palomae, H. rafaelense, H. brevispini and H. cairoense, and 0-1 scales in H. metae and H. boquiae). It further differs from H. colombianus in having a round or oblong humeral spot (vs. rectangular). It can be diagnosed from H. beni, H. dariensis, H. divisorensis, H. helleri, H. huambonicus, H. inambari, H. jabonero, H. jelskii, H. mikrostiktos, H. polyodon, H. quindos, H. raqueliae, H. santamartae, H. surinamensis, H. taeniurus, H. tridens and H. yacopiae by the presence of melanophores on the posterior margins of the scales all along the sides of body (vs. absence of melanophores from margins of scales along entire length of sides of body). It is further distinguished from all congeners mentioned above by having the following characters: a wide, concave pelvicbone (vs. narrow and straight); middle part of the dorsal margin of the orbitosphenoid bone flattened and not in contact with frontal (vs. dorsal margin straight and in contact with frontal); ventral tip of supracleithrum bifurcate (vs. not bifurcate); six teeth in the outer premaxillary row arranged in a straight line (vs. five or fewer teeth in outer premaxillary row and not arranged in straight line, except H. cairoense with two to six teeth in the outer premaxillary row) (Ref. 98056).
Found in streams characterized by relatively rapid water running over rocky and sandy substrates with high transparency. Occurs syntopically with Bryconamericus emperador, Astroblepus sp., Pimelodella sp. and Characidium sp. Feeds on adult and larval insects, nematodes, isopods, and unidentified arthropod fragments. The presence of autochthonous and some allochthonous items in the guts suggests that this species is insectivorous with considerable plasticity in its diet (Ref. 98056).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Román-Valencia, C., R.I. Ruiz-C., D.C. Taphorn and C.A. García-Alzate, 2014. A new species of Hemibrycon (Characiformes, Characidae) from the upper San Juan River drainage, Pacific versant, Colombia. ZooKeys 454:109-125. (Ref. 98056)
IUCN Red List Status (Ref. 130435: Version 2024-1)
Threat to humans
Harmless
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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=0.01413 (0.00635 - 0.03140), b=2.99 (2.80 - 3.18), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.0 ±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 (10 of 100).
