Bryconops transitoria
1915 illustration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Bryconops
Species:
B. transitoria
Binomial name
Bryconops transitoria

Bryconops transitoria is a small freshwater fish that lives in the rivers of South America. It is a poorly-studied member of the genus Bryconops with few records and vague distribution accounts, though it is believed to be endemic to the Rio Tapajós. It was originally thought to be a subspecies of congener Bryconops melanurus, but is now accepted as its own species.

Description

Bryconops transitoria reaches a maximum of roughly 7.0 cm (2.8 in),[1] which places it slightly to the smaller side of the genus Bryconops.[2] It is a silver-colored fish with a darker back and a generally slender body, as is not uncommon with Bryconops as a whole. Otherwise, it is poorly documented, which leads to a lack of distinct physical records.[3]

Congener B. melanurus has noted morphological similarities with B. transitoria, but can be differentiated based on morphometric specifics and differences in fin structure; for instance, B. transitoria has 23-27 anal-fin rays, whereas B. melanurus has 28-29.[4] Nonetheless, these differences are generally minor.

Taxonomy

When first described by Austrian zoologist Franz Steindachner, B. transitoria was listed as a subspecies of Bryconops melanurus, at the time referred to as Creatochanes melanurus var. transitoria.[5] This was corrected in a list by Lima et al. in 2003, in which it was recognized as Bryconops transitoria, a standalone species.[6] The genus Creatochanes has been synonymized with Bryconops and is now considered a subgenus, to which B. transitoria belongs.[4]

Some authorities believe that the validity of B. transitoria as a species needs investigation given its similarity to B. melanurus and its sparse collection records.[4] Said records are known to be vague, and the species itself not particularly well-studied.[7] The syntypes (original collection of specimens upon which a new species description is based) were re-evaluated in 2018, and found to be composed of three different species (one of which was a member of Iguanodectes, a related but separate genus).[3]

Bryconops as a genus was once considered a member of the family Characidae, but research in 2011 prompted that it be moved to a new family, Iguanodectidae.[8] It was placed there alongside the genera Piabucus and Iguanodectes, but while those two make up the subfamily Iguanodectinae, Bryconops is a solitary clade.[9] Today, B. transitoria is considered an iguanodectid rather than a characin.

Etymology

The specific epithet "transitoria" is feminine in Latin. When paired with the Latin "varietas" (signifying a variant of a species), which is also feminine, "transitoria" would be the correct word to use; this was B. transitoria's original placement, when described by Steindachner (as Creatochanes melanurus var. transitoria).[7] However, there has been at least one proposition to change the species name to "transitorius", as "Bryconops" and "Creatochanes" are both considered masculine, and convention states that the names match in the context of linguistic gender.[3]

The specific epithet "transitoria" means "in transition", referring to the fact that B. transitoria was originally speculated to represent a highly-variable subspecies of B. melanurus.[10] In terms of a common name, B. transitoria is one of several members of Bryconops sometimes referred to as "lambari".[11]

Habitat and ecology

Bryconops transitoria is largely considered endemic to the Tapajós basin.[1] More specific preferences include a leaning towards clearwater habitats, as opposed to whitewater or blackwater.[12] However, B. transitoria is also poorly-studied, with unclear distribution records dating all the way back to its discovery.[7] B. transitoria is one of four Bryconops species to be described from the Tapajós; The others are Bryconops gracilis, B. munduruku, and B. durbinae.[4]

While B. transitoria has not been the subject of specific dietary study, it is likely to be an insectivore or omnivore, based on behavior seen in other members of the genus.[13][14]

Conservation status

Bryconops transitoria specifically has not been evaluated by the IUCN.[1] However, its natural habitat in the Tapajós basin is known to be facing various anthropogenic threats; other species of Bryconops are under similar survival pressure.[15]

The Río Tapajos main is a site of frequent consideration for infrastructure and mining developments.[16] This is only from a legal standpoint, however - illegally, there have been instances of unlawful mining kicking up enough sediment to turn the waters of the Tapajós brown. The illegal gold mining industry is a thriving market in Latin America, despite its inherent danger to both participants and the environment.[17][18] Species like B. transitoria are among potential casualties of activity along such lines.

The Tapajós is of such ecological and infrastructural importance that various projects have been reconsidered, specifically taking environmental impact into consideration.[16][19] Therefore, B. transitoria (and the other Tapajós-endemic species) have a greater chance of survival.

References

  1. 1 2 3 Froese, Rainer; Pauly, Daniel (eds.) (2022). "Bryconops transitoria" in FishBase. November 2022 version.
  2. ↑ Froese, Rainer and Pauly, Daniel, eds. (2022). Species of Bryconops in FishBase. November 2022 version.
  3. 1 2 3 Lucinda, Paulo H. F.; Guedes, Tharles L. O. (2 May 2018). "Taxonomic status of the South American characid fish Creatochanes melanurus transitorius Steindachner, 1915 (Teleostei: Characidae)". Ichthyological Exploration of Freshwaters (IEF-1057): 1–3. doi:10.23788/IEF-1057. Retrieved 11 November 2022.
  4. 1 2 3 4 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.
  5. ↑ Steindachner, Franz (1917). "Denkschriften der Kaiserlichen Akademie der Wissenschaften / Mathematisch-Naturwissenschaftliche Classe" (in German). 93. Kaiserlich-Königlichen Hof- und Staatsdruckerei: 49–51. ISSN 0379-0207. OCLC 1478736. Retrieved 11 November 2022. {{cite journal}}: Cite journal requires |journal= (help)
  6. ↑ Wingert, Juliana Mariani; Malabarba, Luiz Roberto (4 April 2011). "Descrição de duas novas espécies de Bryconops (Teleostei: Characidae) da Bacia do Rio Amazonas". hdl:10183/28524. Retrieved 11 November 2022. {{cite journal}}: Cite journal requires |journal= (help)
  7. 1 2 3 Dagosta, Fernando C.P.; Pinna, Mário De (13 June 2019). "The fishes of the Amazon : distribution and biogeographical patterns, with a comprehensive list of species". Bulletin of the American Museum of Natural History. 2019 (431): 75. doi:10.1206/0003-0090.431.1.1. S2CID 196645665. Retrieved 11 November 2022.
  8. ↑ 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.
  9. ↑ Bailly, Nicolas (17 April 2015). "WoRMS taxon details - Iguanodectidae Eigenmann, 1909". World Register of Marine Species. Retrieved 6 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. ↑ da Silva, Solange (2015). "Monitoring and Rescue of Ichthiofauna in the Teles Pires River, in the Area of Influence of the Colider Hydroelectric Plant" (PDF). Mato Grosso State University (Universidade do Estado de Mato Grosso UNEMAT) Quarterly Report. 14: 18. Retrieved 11 November 2022.
  12. ↑ Bogotá-Gregory, Juan David; Lima, Flávio C. T.; Correa, Sandra B.; Silva-Oliveira, Cárlison; Jenkins, David G.; Ribeiro, Frank R.; Lovejoy, Nathan R.; Reis, Roberto E.; Crampton, William G. R. (December 2020). "Biogeochemical water type influences community composition, species richness, and biomass in megadiverse Amazonian fish assemblages". Scientific Reports. 10 (1): 15349. doi:10.1038/s41598-020-72349-0. PMC 7501869. PMID 32948815.
  13. ↑ 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.
  14. ↑ "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
  15. ↑ "Search for "Bryconops"". IUCN Red List. International Union for the Conservation of Nature. Retrieved 10 November 2022.
  16. 1 2 Bradford, Sue (26 August 2016). "Planned Tapajós industrial waterway a potential environmental disaster". Mongabay News. Retrieved 10 November 2022.
  17. ↑ Klein, David (6 May 2022). "Interpol: Illegal Gold Mining is Devastating Latin America". OCCRP. Organized Crime and Corruption Reporting Project. Retrieved 10 November 2022.
  18. ↑ "Illegal Gold Mining". USAID. United States Agency for International Development. 28 June 2022. Retrieved 9 November 2022.
  19. ↑ "The Tapajos River: Hope for Sustainable Development". The Nature Conservancy. The Nature Conservancy. 6 November 2018. Retrieved 10 November 2022.
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