Bryconops vibex

Bryconops vibex
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Bryconops
Species:
B. vibex
Binomial name
Bryconops vibex

Bryconops vibex is a small freshwater fish from the rivers of Venezuela, known solely from the Rio Cataniapo. The body is slender, though with an element of sturdiness, and it has one humeral spot by each pectoral fin. It bears visual similarities to several congeners, but can be differentiated by way of many factors.

Alongside congener Bryconops humeralis, B. vibex was described in a study in 1996.

Description

Bryconops vibex reaches a maximum of roughly 6.8 cm (2.8 inches) in standard length (excluding the tail fin).[2] This makes it one of the smaller members of the genus Bryconops by a thin margin, though most Bryconops are of comparable length (within ~3cm).[3] The fins are dark-tinted but translucent, and the dorsal half of its caudal fin sports an orange or yellowish ocellus (eyespot).[4] Its scales are silver to silver-green in life, which is not uncommon in the genus, and it bears a single humeral spot by each pectoral fin.[5]

Bryconops vibex is similar to many species in the genus, but there are ways to tell it apart. Its single humeral spot can be used to differentiate it from congeners like B. munduruku and B. inpai, both of which have two humeral spots,[6] or from the likes of B. affinis and B. giacopinii, which have none.[7] Its body is shallower than that of B. cyrtogaster (though still robust),[8] and small factors like a thicker caudal peduncle and a higher number of scales beneath the lateral line differentiate it from sister species B. humeralis.[9]

Taxonomy

Along with ten other species, B. vibex is in the subgenus Creatochanes, making its full name Bryconops (Creatochanes) vibex.[6] It has been considered a member of Bryconops since its description in 1996.[9] The specific name "vibex" is Latin for "mark", referring to the humeral spot;[10] this was of note when B. humeralis and B. vibex were first described, as it was thought that B. inpai was the only other species in the genus to sport any kind of humeral spot at all.[9]

The genus Bryconops as a whole was once considered a member of the family Characidae, which is highly variable and has many genera incertae sedis. However, an in-depth study in 2011 determined by way of phylogeny that Bryconops, along with the genera Iguanodectes and Piabucus, should occupy their own family, Iguanodectidae.[11] (Iguanodectes and Piabucus make up the subfamily Iguanodectinae, while the genus Bryconops is its own monophyletic clade.)[12]

Distribution and ecology

B. vibex was originally described from the Orinoco basin, in Venezuela's Amazonas state, wherein it is relatively common.[9] Specifically, it is known from the Rio Cataniapo, which is a tributary of the Rio Orinoco.[1][2] The Cataniapo is a somewhat acidic clearwater river, with a pH that ranges from 5.0 to 6.9.[13]

B. vibex has not been the subject of diet-specific study. Based on the habits of other species of Bryconops, however, it is most likely to be an˜ invertivore or an omnivore.[14][15]

Conservation status

Bryconops vibex has been evaluated by the IUCN as a near-threatened species; the main danger comes from settlement of nearby farmland.[1] There is documented water quality deterioration in the Rio Cataniapo, including elevated levels of fecal matter and illegal pesticides, which is harmful not only to species like B. vibex but to the human population that relies on the river for their water supply.[16]

An additional threat is the illegal mining scene, which is a booming industry in Latin America as a whole. Though the Rio Cataniapo is not threatened directly by mining activity, Venezuela as a region is dense in mining sites.[17]

References

  1. ^ a b c Echevarría, G. 2019. Bryconops vibex. The IUCN Red List of Threatened Species 2019: e.T118038907A118038912. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T118038907A118038912.en. Accessed on 06 November 2022.
  2. ^ a b Froese, Rainer; Pauly, Daniel (eds.). "Bryconops vibex". FishBase. November 2022 version.
  3. ^ Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Bryconops". FishBase. November 2022 version.
  4. ^ Chernoff, Barry; Machado-Allison, Antonio (31 December 2005). "Bryconops". doi:10.5281/zenodo.6265593. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ Chernoff, Barry; Machado-Allison, Antonio. "Bryconops". TreatmentBank. Plazi. Retrieved 11 November 2022.
  6. ^ a b Silva-Oliveira, Cárlison; Canto, André Luiz C.; Ribeiro, Frank Raynner V. (30 July 2015). "Bryconops munduruku (Characiformes: Characidae), a new species of fish from the lower Tapajós River basin, Brazil". Zootaxa. 3994 (1): 133–141. doi:10.11646/zootaxa.3994.1.7. PMID 26250264 – via Biotaxa.
  7. ^ Chernoff, Barry; Machado-Allison, Antonio (13 December 2005). "Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Günther)". Zootaxa. 1094 (1): 23. doi:10.11646/zootaxa.1094.1.1. ISSN 1175-5334 – via Biotaxa.
  8. ^ Silva‐Oliveira, Cárlison; Moreira, Cristiano R.; Lima, Flávio C. T.; Py‐Daniel, Lúcia Rapp (September 2020). "The true identity of Bryconops cyrtogaster (Norman), and description of a new species of Bryconops Kner (Characiformes: Iguanodectidae) from the Rio Jari, lower Amazon basin". Journal of Fish Biology. 97 (3): 860–868. doi:10.1111/jfb.14445. PMID 32584438. S2CID 220060299.
  9. ^ a b c d Machado Allison, Antonio; Chernoff, Barry; Buckup, Paulo (1996). "Bryconops humeralis y B.vibex, dos nuevas especies del genero bryconops kner (1858) para Venezuela". Acta Biologica Venezuela (in Spanish). 16 (2): 45–58. Retrieved 11 November 2022.
  10. ^ Scharpf, Christopher; Lazara, Kenneth J. (15 September 2020). "Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE". The ETYFish Project. Retrieved 11 November 2022.
  11. ^ Oliveira, Claudio; Avelino, Gleisy S.; Abe, Kelly T.; Mariguela, Tatiane C.; Benine, Ricardo C.; Ortí, Guillermo; Vari, Richard P.; Corrêa e Castro, Ricardo M. (December 2011). "Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling". BMC Evolutionary Biology. 11 (1): 275. doi:10.1186/1471-2148-11-275. PMC 3190395. PMID 21943181.
  12. ^ Bailly, Nicolas (17 April 2015). "WoRMS taxon details - Iguanodectidae Eigenmann, 1909". World Register of Marine Species. Retrieved 11 November 2022.
  13. ^ Sajo-Bohus, L.; Greaves, E. D.; Alvarez, H.; Liendo, J.; Vásquez, G.; Alarcon, Ricardo; Cole, Philip L.; Djalali, Chaden; Umeres, Fernando (2007). "Radon Concentration in the Cataniapo-Autana River Basin, Amazonas State, Venezuela". AIP Conference Proceedings. 947 (469): 469–470. doi:10.1063/1.2813855.
  14. ^ Echevarría, Gabriela; González, Nirson (November 2018). "Fish taxonomic and functional diversity in mesohabitats of the River Kakada, Caura National Park, Venezuela". Nature Conservation Research. 3 (Suppl. 2). doi:10.24189/ncr.2018.048. Retrieved 10 November 2022.
  15. ^ "THE FISH FAMILIES". Field Guide to the Fishes of the Amazon, Orinoco, and Guianas, edited by Peter van der Sleen and James S. Albert, Princeton: Princeton University Press, 2017, pp. 95-96. https://doi.org/10.1515/9781400888801-009
  16. ^ Astiz, Simón. (2012). Water resource degradation in the Cataniapo River, Amazons, Venezuela. Tecnologia y Ciencias del Agua. 3. 5-20. Retrieved 11 November 2022.
  17. ^ Caballero, Angie (18 September 2020). "Hortimio, the "Lord of the Earth": Always at the Forefront in Cataniapo". InfoAmazonia. Retrieved 11 November 2022.