| Family: |
Characidae (Characins; tetras), subfamily: Stevardiinae |
| Max. size: |
4.46 cm SL (male/unsexed) |
| Environment: |
benthopelagic; freshwater |
| Distribution: |
South America: currently known from several small drainages entering the Guaviare River basin, Orinoco River basin, Colombia (Ref. 119432). |
| Diagnosis: |
Dorsal soft rays (total): 10-11; Anal soft rays: 27-34; Vertebrae: 40. Diagnosis: Chrysobrycon guahibo differs from its congeners by having fewer maxillary teeth (1-3 vs. 6-15 in C. eliasi, 3-11 in C. hesperus, 3-12 in C. myersi, and 9-16 in C. yoliae), the nasal bone longer than the antorbital (vs. nasal as long as or shorter than antorbital), absence of bony lamella between the 2nd and 3rd basibranchials (vs. presence of this lamella), and bony hooks on the 3rd to 7th branched anal-fin rays with discontinuous arrangement, forming 2 separate series along each ray in mature males (vs. bony hooks with continuous arrangement, forming single series along rays, except in C. hesperus); Chrysobrycon guahibo is also distinguished from C. eliasi, C. myersi and C. yoliae by the posterior margin of the ventral process of the quadrate not reaching the vertical through posterior margin of symplectic (vs. reaching the vertical through posterior margin of symplectic, except in C. eliasi) and the possession of teeth on the 3rd pharyngobranchial (vs. absence of those teeth, except in C. yoliae); Chrysobrycon guahibo differs from C. hesperus and C. myersi by the presence of a terminal lateralline tube between caudal-fin rays 10 and 11 (vs. absence of this tube), absence of bony lamella between the 1st and 2nd basibranchials (vs. presence of this lamella), and greater number of neural spines between the posteriormost supraneural and the anteriormost dorsal-fin pterygiophore (4-5 vs. 2-3); Chrysobrycon guahibo is distinguished from C. myersi and C. yoliae by the body depth at dorsal-fin origin (24-32 % SL vs. 31-42) and dorsal-fin to adipose-fin length (20-26 % SL vs. 27-33); furthermore, C. guahibo differs from C. myersi by the snout to dorsal-fin origin length (63-71 % SL vs. 57-63), dorsal-fin to hypural complex length (31-39 % SL vs. 40-47), eye to dorsal-fin origin length (51-58 % SL vs. 46-49), upper jaw length (39-48 % HL vs. 49-55), number of vertebrae located anterior to the 1st proximal pterygiophore (19 vs. 15), and number of circumpeduncular scales (14-16 vs. 17-19); Chrysobrycon guahibo differs from C. yoliae by having a lesser dorsal-fin base length (7-11 % SL vs. 12-14) and fewer dentary teeth (9-14 vs. 20-26) (Ref. 119432). |
| Biology: |
|
| IUCN Red List Status: |
Vulnerable (VU); Date assessed: 07 October 2020 (B1ab(iii)+2ab(iii)) Ref. (130435)
|
| Threat to humans: |
harmless |
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