Tailspot tetra

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Tailspot tetra
Bryconops cf caudomaculatus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Bryconops
Species:
B. caudomaculatus
Binomial name
Bryconops caudomaculatus
Günther, 1864
Synonyms

Tetragonopterus caudomaculatus Günther, 1864
Creatochanes caudomaculatus Eigenmann, 1924

Contents

The tailspot tetra (Bryconops caudomaculatus) is a freshwater fish that lives in the coastal river regions of upper South America. Both its common and scientific names reference the distinct spot of color present on the tail fin, which is one of its defining characteristics. It is a small fish, reaching 4.8 in (12.4 cm) at its longest. Despite its small size, it is an active swimmer, with a preference for fast-flowing waters.

Description

The tailspot tetra, like the rest of the genus Bryconops , has a slender body described as "smelt-like", similar to members of sister genus Piabucus . [1] It reaches 4.8 in (12.4 cm) in total length (with the tail fin included), and a corresponding weight of 20.1 grams. [2] Its back scales are tinted orange to dark-orange, fading into silver on the belly when the fish is alive. Upon close inspection, the scales are also revealed to have a scattering of minute dots. [3]

The spot of bright orange on the basal half of the caudal fin is what gives the tailspot tetra its common name. The scientific name also reflects this - "caudo-" is in reference to the caudal fin (the tail fin), and "-maculatus" means "spotted" (compare with the word "immaculate", which means "without blemishes"). [4] Though it is more vivid in life, this spot of color may turn pale upon preservation of a given specimen. [5]

Visually, the tailspot tetra is easy to confuse with congeners B. magoi and B. collettei , which means that they have often been misidentified as B. caudomaculatus. [6] (This is part of the reason they are considered to be in the same species complex.) Recent congener B. florenceae was also previously misidentified as B. caudomaculatus before its distinction as a separate species. [7]

The lateral line is usually incomplete. Some specimens of B. caudomaculatus display a particularly truncated lateral line that makes them appear more visually similar to B. durbini . [5] Another recently named congener, Bryconops piracolina , is visually similar, but with a difference in the lateral line - it has a smaller number of pored lateral line scales than B. caudomaculatus. [8]

Taxonomy

In 1864, Albert Günther gave the tailspot tetra the scientific name Tetragonopterus caudomaculatus when he first described it as a new species. [9] The genus Tetragonopterus is closely related to the genus Bryconops, and therefore an element of viability remains in Günther's original placement. [5] Ichthyologist Carl H. Eigenmann placed B. caudomaculatus into the genus Creatochanes, which was later classified as a subgenus of Bryconops, to which B. caudomaculatus no longer belongs; Instead, it is considered Bryconops (Bryconops) caudomaculatus. [5] [10]

The tailspot tetra is the type species of the Bryconops caudomaculatus species complex, which includes B. caudomaculatus, B. disruptus, B. durbini, B. collettei, and B. magoi. [6] This complex is not official, but species have been placed in it based upon phenotypic similarities and a history of synonymy with Bryconops caudomaculatus. [11] Due to striking visual similarities and subsequent routine misidentification, B. florenceae (named in 2021) is a candidate for the complex, though this has not been professionally recognized. [7]

The genera Bryconops, Iguanodectes, and Piabucus were previously in the family Characidae, which is incredibly variable and has many genera incertae sedis. [12] In 2011, however, research by Oliveira et al. prompted the three to be moved to the family Iguanodectidae, which was revived from Eigenmann's previous work. [13] [14] The tailspot tetra's classification as a characiform fish in the family Iguanodectidae is its current accepted position. [15]

Habitat and ecology

A 1912 illustration of several South American freshwater fishes, with B. caudomaculatus at the bottom. The freshwater fishes of British Guiana, including a study of the ecological grouping of species and the relation of the fauna of the plateau to that of the lowlands (1912) (14756941976).jpg
A 1912 illustration of several South American freshwater fishes, with B. caudomaculatus at the bottom.

The tailspot tetra is an active swimmer, with a physiology that reflects this despite its small size. [16] Its chosen habitat is also linked to its swimming strength, as it has a noted preference for fast-flowing waters with rocky substrate. [2] It is also not an uncommon sight in a contrasting home - slow-moving blackwater environments. [5] Its morphology differs based upon where it lives (in a running water channel as opposed to a lagoon); studies have shown that examination based upon physical aspects can correctly classify at least 75% of any given specimens' habitats. [17] More of the body weight is shifted backwards for tailspot tetras that live in lagoon habitats, and the mouth is slightly more upturned for channel-dwelling tetras.

A study in January of 2022 tested the effects of aluminum in the tailspot tetra's environment, as aluminum is soluble in acidic waters and has been linked to cardiotoxic damage after prolonged exposure. [18] Researchers determined that an aluminum concentration of 3.0 mg/L has a high likelihood of leading to an atrioventricular block in B. caudomaculatus, meaning that the heart's ability to beat effectively gets compromised due to interruption (blockage) of the responsible electrical impulse. [19]

Prey and predators

As part of its omnivorous diet, the tailspot tetra will actively leap from the water to target flying insects, especially during the twilight hours. [20] It also has a marked taste for insects that have not yet matured, as opposed to the mature terrestrial forms that have moved onto land. [21] It is unknown if varying habitats, and therefore varying morphologies, have a distinct effect on specific diet composition, though it is speculated that this could be the case. [17]

In turn, the tailspot tetra is not only a regular part of the food chain as a source for animals that eat small fish, but it is also preyed upon by parasites. In 2011, B. caudomaculatus was discovered to be the host for a new species of trematode (parasitic flatworm), Auriculostoma foliaceum (which is currently accepted as Creptotrema foliaceum). [22] [23]

Conservation status

Though the tailspot tetra's conservation status has not been evaluated, it is known to be taken from the wild in places including Guyana, Peru, and Venezuela for export in the aquarium industry, especially in the United Kingdom. [24] Despite this, it remains common in many places, including areas disrupted by the construction of the Balbina Hydroelectric Dam in Brazil. [21] Its ability to adapt to its surroundings combined with a flexible diet make it unlikely to become endangered.

Related Research Articles

<i>Bryconops</i> Genus of fishes

Bryconops is a genus of freshwater fish in the family Iguanodectidae from South America. It consists of small fish, all under half-a-foot long, with slender bodies and silvery scales, though there is some mild color variation. Several species can be identified by way of a humeral patch, and others have a reddish ocellus, or eyespot, on one or both lobes of the dorsal fin.

<span class="mw-page-title-main">Iguanodectidae</span> Family of fish

Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra, the tailspot tetra, and the orangefin tetra, are sometimes taken as aquarium fish.

<span class="mw-page-title-main">Orangefin tetra</span> Species of fish

The orangefin tetra is a small species of freshwater fish from South America that belongs to the family Iguanodectidae. Though common in its native range, it seems to prefer fast-flowing and shallow creeks. It is an active swimmer that feeds on plant material and various invertebrates, sometimes jumping out of the water to catch prey above the surface.

<i>Bryconops alburnoides</i> Species of fish

Bryconops alburnoides is a small freshwater fish, approximately 6 inches long at its largest, that lives in the rivers of South America. It has a slender body, with a yellowish dorsal fin and yellow-tinged back scales that fade into silver on its belly. It is largely an insectivore that picks land-dwelling insects from the riverbanks, though it eats much more whenever rain washes prey into the water.

Bryconops colanegra is a small, slender-bodied species of freshwater fish from South America, about 3.5 in long. It has a black tail fin that bears hints of red, and its scales are dark along the back, transitioning to a silver belly. It is endemic to a single river system in Venezuela, the Rio Caroní.

<i>Bryconops colaroja</i> Species of fish

Bryconops colaroja is a small species of fish endemic to tributaries and creeks of the Cuyuni River basin in Venezuela. The specific epithet "colaroja" means "red tailed", and it gets this name from its most distinctive feature - a deep red caudal fin, largely unique amongst members of its genus.

<i>Bryconops collettei</i> Species of fish

Bryconops collettei is a small freshwater fish from the rivers of South America. It is mostly silvery, with notable green iridescence on its sides, and a diffuse ocellus (eyespot) on the upper lobe of the caudal fin. Before its distinction as a separate species, specimens of B. collettei were misidentified as specimens of Bryconops caudomaculatus due to several morphological similarities, including a caudal ocellus and generally similar fin coloration.

Bryconops disruptus is a small freshwater fish of the family Iguanodectidae. It is only found in the Rio Negro in South America. Like the rest of the genus Bryconops, B. disruptus is silvery in color, with a relatively deep chest and a notable set of teeth. The specific epithet "disruptus" refers to the incomplete lateral line.

Bryconops durbinae, sometimes listed under the name Bryconops durbini, is a small species of freshwater fish in the family Iguanodectidae. It is the smallest species of the genus Bryconops, and is endemic to the Tapajós river basin in Brazil.

<i>Bryconops giacopinii</i> Species of fish

Bryconops giacopinii is a mid-sized species of freshwater fish in the family Iguanodectidae. It is the largest member of the genus Bryconops, and is therefore difficult to confuse with any of its congeners. With a diet that consists largely of land-dwelling insects, it serves as an important link between the terrestrial and aquatic aspects of its native range.

<i>Bryconops gracilis</i> Species of fish

Bryconops gracilis is a small species of freshwater fish from the rivers of South America. It is one of multiple species for which the common name "lambari" is used. Though not well-studied, it has been re-described in recent years in order to differentiate it from Bryconops alburnoides, a congener to which it bears a strong resemblance.

Bryconops humeralis is a small freshwater fish distributed across northern South America. The name "humeralis" means "relating to the shoulder", in reference to the distinct humeral patches that the fish sports. It is slightly longer than average in terms of the genus Bryconops, though still firmly within the standard range, and is slightly more slender than is usual for its congeners.

Bryconops imitator is a small freshwater fish that lives in the rivers of South America. It is a small, silvery fish with a bright red tail fin that is known to eat invertebrates, like insects and freshwater zooplankton.

Bryconops inpai is a small freshwater fish native to the rivers of South America. It only lives in two particular river systems - the Casiquiare and Negro - which means that its range is restricted to the northern half of the continent. It has indistinct humeral spots, and is bluish-silver in life, which is unusual for members of Bryconops; they are more often plain silver or greenish-silver.

<i>Bryconops magoi</i> Species of fish

Bryconops magoi is a small species of fish from South America. It is only found in Venezuela, along with sister species Bryconops collettei. Its tail-fin markings help to differentiate it from various congeners, as does its fairly restricted range. It is most closely related to B. collettei and Bryconops caudomaculatus, and it was once considered synonymous with the latter; specimens of B. magoi and B. collettei both were routinely misidentified as B. caudomaculatus before being given species distinction.

<i>Bryconops melanurus</i> Species of fish

Bryconops melanurus, sometimes called the tail-light tetra, is a small species of freshwater fish from South America that primarily preys on insects. It lives in small schools and is an active swimmer, which means that it requires open space in its habitat. Nonetheless, it does not demonstrate a strong preference for any one biotope within its native range.

<i>Bryconops piracolina</i> Species of fish

Bryconops piracolina is a small fish that inhabits the waters of Brazil. It is slender and silvery in color, like many fish in Bryconops, but can be distinguished from other members by way of its dorsal fin, which has a black patch of color extending up from the fin-base; congeners usually have light pigment in the dorsal fin, or a brighter color.

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.

Bryconops allisoni is a species of freshwater fish known from the rivers of Brazil. It is a recent addition to the genus (2019), currently considered a member incertae sedis. Its name honors Antonio Machado-Allison, an ichthyologist responsible for a great deal of work on the genus Bryconops.

<i>Bryconops florenceae</i> Species of fish

Bryconops florenceae is a small freshwater fish that inhabits the rivers of South America. Comprehensive research is lacking due to B. florenceae being the most recently described of the genus, but researchers believe it to be a relatively widespread species. It is found throughout the Maroni, Mana, and Sinnamary river basins, which defines its range within Suriname and French Guiana.

References

  1. ↑ "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
  2. 1 2 Froese, Rainer; Pauly, Daniel (eds.) (2022). "Bryconops caudomaculatus" in FishBase . April 2022 version.
  3. ↑ Cockerell, Theodore D. A. (September 1914). "The scales of the South American Characinid fishes". Annals of the Carnegie Museum. 9 (1–2): 103. doi: 10.5962/p.331043 . S2CID   251481912 . Retrieved 6 April 2022.
  4. ↑ Scharpf, Christopher; Lazara, Kenneth J. (15 September 2020). "Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE". The ETYFish Project. Retrieved 6 April 2022.
  5. 1 2 3 4 5 Machado-Allison, Antonio & Buckup, Paulo & Chernoff, Barry & Royero, Ramiro. (1993). Las especies del genero Bryconops Kner, 1858 en Venezuela (Teleostei, Characiformes). 14. 1-20.
  6. 1 2 Chernoff, Barry & Machado-Allison, Antonio. (2005). Bryconops magoi and Bryconops collettei (Characiformes: Characidae), two new freshwater fish species from Venezuela, with comments on B. caudomaculatus (Günther). Zootaxa. 1094. 10.11646/zootaxa.1094.1.1.
  7. 1 2 Silva-Oliveira, Cárlison; Ota, Rafaela P.; Sabaj, Mark H.; Py-Daniel, Lúcia H. Rapp (2021-12-13). "A new species of Bryconops (Characiformes: Iguanodectidae) from Atlantic coastal drainages of Suriname and French Guiana". Neotropical Ichthyology. 19 (4). doi: 10.1590/1982-0224-2021-0113 . ISSN   1679-6225. S2CID   245224953.
  8. ↑ Wingert, Juliana M.; Malabarba, Luiz R. (2011). "A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil". Neotropical Ichthyology. 9 (3): 471–476. doi: 10.1590/S1679-62252011000300002 . hdl: 10183/81588 . ISSN   1679-6225.
  9. ↑ Bryconops caudomaculatus (Günther, 1864) in GBIF Secretariat (2021). GBIF Backbone Taxonomy. Checklist dataset doi : 10.15468/39omei accessed via GBIF.org on 2022-04-06.
  10. ↑ Eigenmann, Carl H.; Meyers, George S. (1917–1929). The American Characidae. Cambridge. pp. 493–499. Retrieved 3 April 2022.
  11. ↑ Chernoff, Barry; Machado-Allison, Antonio (2005-12-31). "Bryconops (Bryconops)". doi:10.5281/ZENODO.6265583.{{cite journal}}: Cite journal requires |journal= (help)
  12. ↑ Lima, Flávio & Malabarba, Luiz & Buckup, Paulo & Pezzi da Silva, José & Vari, Richard & Harold, Antony & Benine, Ricardo & Oyakawa, Osvaldo & Pavanelli, C. & Menezes, Naercio & Lucena, Carlos & Malabarba, Maria & Lucena, Zilda & Reis, Roberto & Langeani, Francisco & Cassati, Lilian & Bertaco, Vinicius & Moreira, Cristiano & Lucinda, Paulo. (2003). Genera incertae sedis in Characidae.
  13. ↑ Froese, Rainer, and Daniel Pauly, eds. (2022). "Iguanodectidae" in FishBase . April 2022 version.
  14. ↑ Oliveira, C., Avelino, G.S., Abe, K.T., Mariguela, T.C., Benine, R.C., Orti, G., Vari, R.P., & Correa e Castro, R.M. (2011): Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.  BMC Evolutionary Biology, 11: 275. doi : 10.1186/1471-2148-11-275
  15. ↑ Bailly, Nicolas (17 February 2022). "WoRMS taxon details - Bryconops caudomaculatus (Günther, 1864)". World Register of Marine Species . Retrieved 6 April 2022.
  16. ↑ Cantanhêde, Sildiane Martins; Hamoy, Moisés; Montag, Luciano Fogaça de Assis; Amado, Lílian Lund (February 2020). "Electrophysiological responses in Amazonian fish species Bryconops caudomaculatus (Osteichthyes: Characiformes) as biomarkers of xenobiotic toxicity". Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 228: 108653. doi:10.1016/j.cbpc.2019.108653. PMID   31683014. S2CID   207890756.
  17. 1 2 Langerhans, Brian & Layman, Craig & LANGERHANS, AIMEE & Dewitt, Thomas. (2003). Habitat-associated morphological divergens in two Neotropical fish species. Biological Journal of the Linnean Society. 80. 689 - 698. 10.1111/j.1095-8312.2003.00266.x.
  18. ↑ Ghorbel, Imen; Elwej, Awatef; Chaabane, Mariem; Jamoussi, Kamel; Zeghal, Najiba (2017-08-01). "Protective effect of selenium against aluminium chloride induced cardiotoxicity in rats". Pharmaceutical and Biomedical Research. 3 (2): 19–25. doi: 10.29252/pbr.3.2.19 . ISSN   2423-4486.
  19. ↑ Cantanhêde, Sildiane Martins; de Carvalho, Irina Sofia Cardoso; Hamoy, Moisés; Corrêa, José Augusto Martins; de Carvalho, Leandro Machado; Barbas, Luis André Luz; Montag, Luciano Fogaça de Assis; Amado, Lílian Lund (2022-01-01). "Evaluation of cardiotoxicity in Amazonian fish Bryconops caudomaculatus by acute exposure to aluminium in an acidic environment". Aquatic Toxicology. 242: 106044. doi:10.1016/j.aquatox.2021.106044. ISSN   0166-445X. PMID   34861573. S2CID   244872116.
  20. ↑ Costa-Pereira, Raul; Severo-Neto, Francisco (June 2012). "Dining out: Bryconops caudomaculatus jumps out of water to catch flies". Revista chilena de historia natural. 85 (2): 241–244. doi: 10.4067/S0716-078X2012000200012 . ISSN   0716-078X.
  21. 1 2 Silva, Cylene C. da; Ferreira, Efrem J. G.; Deus, Cláudia P. de (2008). "Diet of Bryconops alburnoides and B. caudomaculatus (Osteichthyes: Characiformes) in the region affected by Balbina Hydroelectric Dam (Amazon drainage, Brazil)". Neotropical Ichthyology. 6 (2): 237–242. doi: 10.1590/S1679-62252008000200011 . ISSN   1679-6225.
  22. ↑ Curran, Stephen S., et al. “PHYLOGENETIC AFFINITIES OF AURICULOSTOMA (DIGENEA: ALLOCREADIIDAE), WITH DESCRIPTIONS OF TWO NEW SPECIES FROM PERU.” The Journal of Parasitology, vol. 97, no. 4, 2011, pp. 661–70, http://www.jstor.org/stable/23019184. Accessed 6 Apr. 2022.
  23. ↑ Gibson, David (20 November 2021). "WoRMS taxon details - Creptotrema foliaceum (Curran, Tkach & Overstreet, 2011) (Franceschini, Aguiar, Zago, de Oliveira Fadel Yamada, Bertholdi Ebert & da Silva, 2021)". World Register of Marine Species . Retrieved 6 April 2022.
  24. ↑ Prang, Gregory. (2007). An industry analysis of the freshwater ornamental fishery with particular reference to the supply of Brazilian freshwater ornamentals to the UK market. Uakari. 3. 10.31420/uakari.v3i1.18.
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