Astyanax bourgeti

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Astyanax bourgeti
Astyanax bourgeti illustration (1917).jpg
1917 illustration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Astyanax
Species:
A. bourgeti
Binomial name
Astyanax bourgeti
Eigenmann, 1908

Astyanax bourgeti is a small species of freshwater fish native to the upper Amazon river in Brazil. Originally described in 1908, it is not a particularly well-studied member of the genus Astyanax , but there is enough information available to establish a native range, an appearance, and potential relationships to congeners; for example, A. bourgeti is a known member of the subgenus Poecilurichthys, and has been considered such for most of its existence. Biotope preferences, sympatry, diet, and behavior are all unknown.

Contents

Its gray scales, dark humeral spot, and silver lateral stripe are not uncommon features within the genus, but A. bourgeti can be told apart from congeners by means including the number scales in the lateral line and the number of anal-fin rays. It also has a smaller, silver spot slightly above and behind the normal humeral spot, which isn't as common as its other markings. Besides this, it also has darkened anal, pelvic, and ventral fins, which are somewhat unusual for a species of Astyanax.

Taxonomy

Astyanax bourgeti was originally described by German-American ichthyologist Carl H. Eigenmann in 1908, as one of various nomenclatural acts performed based upon the Thayer expedition to Brazil, which was an 1865 trip directed by Swiss-American biologist Louis Agassiz. [2] [3] Since then, its scientific name has not changed, and it has no known synonyms, with the exception of an occasional reference as A. boulengeri instead. [4] [5]

There are three subgenera in Astyanax (Astyanax, Poecilurichthys, and Zygogaster); [6] of these, A. bourgeti belongs to Poecilurichthys. [7]

Etymology

The specific name "bourgeti" is to honor the collaborator responsible for collecting the type specimens, a French naturalist living in Rio de Janeiro simply credited as "Monsieur Bourget" in the original description and as "D. Bourget" in the accounts of the original voyage to Brazil. [3] [8] Further research unearths naturalist Jean-Baptiste Dieudonné Bourget as the likely identity of this namesake. [9] [10]

Astyanax bourgeti lacks a common name, but is one of various small fishes referred to as "sardinita" in Spanish and "piaba" in Portuguese. [11] [12]

Description

Astyanax bourgeti reaches 9.2 cm (3.6 in) total length. [13] The snout is pointed, and the jaw is roughly the same length as the eye. There are 11 rays on the dorsal fin, 34 rays on the anal fin, and roughly 53 scales in the lateral line. [14] The high number of lateral-line scales is a feature shared with congeners Astyanax cordovae and Astyanax microlepis , [15] as well as Astyanax elachylepis ; the lattermost of these can be readily differentiated from A. bourgeti due to the lower number of anal-fin rays on A. elachylepis. [16] Sexual dimorphism is unknown.

Astyanax bourgeti is a base silver color, and has a distinct dark humeral spot in a flattened oval shape, with a smaller silvery spot above the upper-back edge of the first. It has a narrow lateral stripe in rather faint silver. Its anal fin is a uniform dark color, and its pectoral and ventral fins also sport conspicuous pigmentation, though not as uniform. [3] There is no spot on the caudal peduncle directly, which can help differentiate A. bourgeti from some congeners, but the middle rays of the caudal fin remain darkened. [17] There may be an "echo" of the humeral spot behind the first, not often well-defined; this marking is shared with several species known to be in the Astyanax bimaculatus species complex, such as Astyanax abramis and Astyanax orthodus , which both demonstrate a well-defined humeral spot and faint vertical bars in the humeral region. [18]

Distribution and ecology

Astyanax bourgeti is a species endemic to the Amazon basin, found only within the main channel of the Amazon river. [19] Specifically, it is found in the upper Amazon, in the portions sometimes referred to as the Solimões. [20] The type specimen was originally collected from the Solimões at Tabatinga, Brazil, in 1865. [13] Little is known of specific biotope preferences, or of diet and sympatry.

The Solimões river is an alluvial river with heavy sediment carry. (Alluvial rivers are rivers without a single set form, due to flowing through loose substrate that is easily affected by floods in the region.) Its channels have not demonstrated high amounts of movement, as they are held in by the cliffs of the Alter do Chão Formation. [21] The sediments carried in the Solimões are often rich in nutrients, which contributes to the biodiversity of the Amazon. [22]

Conservation status

Astyanax bourgeti has been evaluated by the IUCN Red List as "Least Concern". [1] The Brazilian ecological organization Chico Mendes Institute for Biodiversity Conservation gave it a data deficient listing in 2014 due to its generally understudied nature. [12] There is already security for the species, however, in the form of the Central Amazon Conservation Complex, which has its approximate center at the confluence of the Solimões and Negro rivers. [23] Because of the region's protected status, the area - and therefore A. bourgeti - is not at particular risk, as far as conservation goes. [24]

Related Research Articles

<i>Astyanax</i> (fish) Genus of fishes

Astyanax is a genus of freshwater fish in the family Characidae of the order Characiformes. Some of these fish, like many of their relatives, are kept as aquarium pets and known collectively as tetras. With around 150 described species and new ones being described yearly, this genus is among the largest of the entire order; Hyphessobrycon also has more than 145 species and which one is larger at any one time depends on whether more species have been recently described in one or the other. The blind and colorless cave tetra of Mexico is a famous member of the genus, but its taxonomic position is disputed: Some recognize it as part of the Mexican tetra and this is supported by phylogenetic evidence, but others recognize the cave form as a separate species, A. jordani.

<i>Deuterodon pelecus</i> Species of fish

Deuterodon pelecus is a species of characid fish from Brazil. It can be distinguished from other species by: its body depth ; its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. D. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Other Deuterodon species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the Greek pelekus, meaning "axe", referring to the pigmentation shape resulting from the adjoinment of the humeral spot with the midlateral stripe.

<i>Carlastyanax</i> Genus of fishes

Carlastyanax aurocaudatus is a small species of freshwater fish in the family Characidae native to the Río Cauca in Colombia. It is the only member of the monotypic genus Carlastyanax, which was named in 1972 specifically for the species by Jacques Géry. Upon description, it was named Astyanax aurocaudatus by Carl H. Eigenmann. There has been debate concerning whether or not the genus should be recognized, but C. aurocaudatus is currently considered a valid species.

<i>Astyanax argentatus</i> Species of fish

Astyanax argentatus is a small freshwater fish native to northern Central America and southern North America. Given its native range, it is also known as the Texan tetra. Little has been published regarding the feeding habits or behavior of A. argentatus, but it is known to have the northernmost distribution of any member of the genus Astyanax.

<i>Astyanax abramis</i> Species of fish

Astyanax abramis is a small freshwater fish from the inland rivers of South America. It is plentiful in almost the entire continent, with a habitat including the La Plata, upper Amazon, and Meta River basins. The body shape is subrhomboidal and laterally compressed, and the scales are largely silver, with a blue or green tint on the dorsal side.

<i>Astyanax angustifrons</i> Species of fish

Astyanax angustifrons, sometimes referred to as the Campeche tetra, is a small freshwater fish from the rivers of Central and South America. It has a healthy distribution across southern Mexico and northern Guatemala, and is relatively common within its native range. Details regarding its diet and behavior are sparse, but it lives in areas with plentiful riparian vegetation, and most other members of the genus are omnivorous. Its habitat includes places affected by pollution and human activity; nonetheless, it is not endangered.

<i>Astyanax aramburui</i> Species of fish

Astyanax aramburui is a small freshwater fish from the rivers of South America, restricted to a relatively small region within the Paraná and Uruguay river basins of Argentina. It was named after the scientist who established a professional presence for ichthyology in the country, Raúl Arámburu. Considered a near-threatened species by the IUCN, its range includes creeks in a sub-basin affected by various forms of pollution.

<i>Astyanax argyrimarginatus</i> Species of fish

Astyanax argyrimarginatus is a small species of freshwater fish native to various river basins in Brazil. Originally thought to be restricted to the Tocantins-Araguaia river system, a study in 2012 expanded its range to include the Rio Xingu, as well. Specific biotope preferences are unknown, but it is mostly collected from clearwater streams in fairly good health. Its relative abundance and presence in some protected locales means that it is not endangered.

<i>Astyanax asuncionensis</i> Species of fish

Astyanax asuncionensis is a small species of freshwater fish described in 1972 from Asunción, the capital of Paraguay in South America. Its specific epithet is in reference to this. Currently, its range is known to encompass areas of not just Paraguay but also Argentina and Brazil. It is an adaptable, omnivorous species that easily lives in sympatry with various congeners.

<i>Astyanax atratoensis</i> Species of fish

Astyanax atratoensis is a small freshwater fish that occupies the Atrato river basin in Colombia. Originally described from a tributary therein, the Truandó River, it gets its specific epithet from the region. Though it faces no imminent threats, A. atratoensis inhabits waterways with a history of severe environmental pressure in the form of anthropogenic pollution. Several restoration efforts have been undertaken in the relevant regions.

<i>Astyanax bagual</i> Species of fish

Astyanax bagual is a small species of freshwater fish known only from the Taquari-Antas river basin in southern Brazil. It is unusual in the genus Astyanax because mature male specimens display bony hooks on the rays of all fins; in opposition, most others have them on the anal, pelvic, or pectoral fins - sometimes on more than one of these, but very rarely on all fins. It can further be told apart from various congeners by way of dentition and some aspects of coloration, including the presence of two humeral spots instead of one.

<i>Astyanax belizianus</i> Species of fish

Astyanax belizianus is a small freshwater fish native to various regions of Central America. Little is known of its diet or specific environmental preferences, but it was first recorded in Belize. Modern ichthyology has expanded its range into Guatemala and Honduras, where it inhabits various rivers and lake tributaries. It is a silvery fish that may have a slight yellowish tint to its scales. The body is deep, especially in comparison to similar species from the same genus.

<i>Astyanax bimaculatus</i> Species of fish

The twospot astyanax, also called the two-spot tetra, is a small species of freshwater fish native to South America. It is a middlingly common tetra in the aquarium industry, with hobbyist reports of its sale and presence, and it is also a well-studied member of the genus Astyanax in wild settings. Amateur aquarists report peaceful schooling behavior in captivity, though fish in wild schools may turn on one another if presented with the threat of a predatory species.

<i>Astyanax brachypterygium</i> Species of fish

Astyanax brachypterygium is a small species of freshwater fish endemic to a collection of high-elevation streams in Brazil. It was named in 2001 alongside congener Astyanax cremnobates, to which it bears a strong resemblance; physical details help to differentiate between the two. Its scales are a greenish-brown on the back and silver on the belly, with reddish fins and a dark humeral spot. One of its defining features is a notably short anal-fin base, which has 13 to 15 rays.

<i>Astyanax brevirhinus</i> Species of fish

Astyanax brevirhinus is a small species of freshwater fish known only from a river basin in northeastern Brazil. It is somewhat understudied and lacks a conservation status, but it is present in a region that is the subject of an ecological restoration project - the Jequitinhonha River. Specifics of diet and behavior are unknown, though shoaling activity has been observed in laboratory conditions.

<i>Astyanax caucanus</i> Species of fish

Astyanax caucanus is a small species of freshwater fish only found in Colombia. While little research exists regarding its ecological habits, such as diet and mating practices, its environment preferences are known to include marshy lowlands, and it easily lives in sympatry with various other fish species in the Cauca and Magdalena river basins. It is not known to share a habitat with any other species of Astyanax, but has a noted phyletic relationship to a group of congeners including Astyanax filiferus, Astyanax stilbe, and Astyanax magdalenae.

Astyanax apiaka is a small freshwater fish endemic to the Apiacá river in Mato Grosso, Brazil. Its discovery is recent, as of 2023, which results in little published research of its natural behaviors or preferred biotopes. However, descriptions of its appearance and general environment have been solidified, as well as some baseline information regarding its diet. It lacks a conservation status from the IUCN.

<i>Astyanax clavitaeniatus</i> Species of fish

Astyanax clavitaeniatus is a small species of freshwater fish native to various rivers in the Amazon basin. It is characterized by a club-shaped lateral stripe, which is where it gets its scientific name; "clava" means "club", and "taenia" means "stripe". It is a deep-bodied fish with a silvery base color, which is not uncommon for members of Astyanax. Its markings - including a humeral spot and two vertical brown bars - indicate that it is a part of a species complex centered around congener Astyanax bimaculatus.

<i>Deuterodon oyakawai</i> Species of fish

Deuterodon oyakawai is a small species of characin endemic to a large river basin along the Atlantic coast in southeast Brazil. It was originally one of three members of the genus Probolodus, but Probolodus is now considered obsolete, synonymized with Deuterodon. Much like other members of Deuterodon, and like some species in related genera, D. oyakawai is a small, silvery fish with fins in some combination of red and clear. It has a defined humeral spot that can be used for identification.

<i>Deuterodon sazimai</i> Species of fish

Deuterodon sazimai is a small freshwater fish endemic to a handful of river basins in southeastern Brazil. Upon being first described, it was considered a member of genus Probolodus; Probolodus is now considered obsolete, synonymized with Deuterodon. Much like other members of Deuterodon, and like some species in related genera like Astyanax or Jupiaba, D. oyakawai is a silvery fish with fins in some combination of red and clear. It sports a wedge-shaped humeral spot, and an oval-shaped blotch on its tail joint.

References

  1. 1 2 Lima, F. (2023). "Astyanax bourgeti". IUCN Red List of Threatened Species . 2023: e.T49830034A159049252. doi: 10.2305/IUCN.UK.2023-1.RLTS.T49830034A159049252.en . Retrieved 7 May 2024.
  2. ↑ "Astyanax bourgeti Eigenmann, 1908". www.zoobank.org. International Commission on Zoological Nomenclature. Retrieved 6 June 2023.
  3. 1 2 3 Eigenmann, Carl H. (1908). "Preliminary descriptions of new genera and species of tetragonopterid characins. (Zoölogical Results of the Thayer Brazilian expedition.)". Bulletin of the Museum of Comparative Zoology at Harvard College. 52 (6): 95–96. Retrieved 6 June 2023.
  4. ↑ Bailly, Nicolas (2017). "Astyanax bourgeti Eigenmann, 1908". WoRMS. World Register of Marine Species . Retrieved 6 June 2023.
  5. ↑ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species related to Astyanax bourgeti". Catalog of Fishes . California Academy of Sciences . Retrieved 6 June 2023.
  6. ↑ Rossini, Bruno César; Oliveira, Carlos Alexandre Miranda; Melo, Filipe Augusto Gonçalves de; Bertaco, Vinicius de Araújo; Astarloa, Juan M. Díaz de; Rosso, Juan J.; Foresti, Fausto; Oliveira, Claudio (19 December 2016). "Highlighting Astyanax Species Diversity through DNA Barcoding". PLOS ONE. 11 (12): e0167203. doi: 10.1371/journal.pone.0167203 . PMC   5167228 . PMID   27992537.
  7. ↑ Riuz-C, Raquel I.; Román-Valencia, César; Taphorn, Donald C.; Buckup, Paulo A.; Ortega, Hernán (8 February 2018). "Revision of the Astyanax orthodus species-group (Teleostei: Characidae) with descriptions of three new species". European Journal of Taxonomy (402). doi: 10.5852/ejt.2018.402 .
  8. ↑ Scharpf, Christopher; Lazara, Kenneth J. (29 December 2022). "Order CHARACIFORMES: Family CHARACIDAE: Subfamily STETHAPRIONINAE (a-g)". The ETYFish Project. Retrieved 30 May 2023.
  9. ↑ Antunes, Anderson Pereira (2015). A rede dos invisíveis: uma análise dos auxiliares na expedição de Louis Agassiz ao Brasil (1865-1866) (PDF) (Master's). Oswaldo Cruz Foundation . Retrieved 6 June 2023.
  10. ↑ Antunes, Anderson Pereira; Massarani, Luisa Medeiros; Moreira, Ildeu de Castro (19 June 2016). "Uma análise da rede de auxiliares na expedição de Louis Agassiz ao Brasil (1865-1866)". Revista Brasileira de História da Ciência. 9 (1): 111–125. doi: 10.53727/rbhc.v9i1.149 .
  11. ↑ "Astyanax bourgeti Eigenmann 1908". Encyclopedia of Life . National Museum of Natural History.
  12. 1 2 "Astyanax bourgeti Eigenmann, 1908". ala-bie.sibbr.gov.br. Brazilian Biodiversity Information System. Retrieved 6 June 2023.
  13. 1 2 Black, Nina. "MCZ Ichthyology 89557". mczbase.mcz.harvard.edu. Harvard Museum of Comparative Zoology. Retrieved 6 June 2023.
  14. ↑ Eigenmann, Carl H.; Myers, George S. (1917). "The American Characidae / by Carl H. Eigenmann". Memoirs of the Museum of Comparative Zoology at Harvard College. 43 (3): 244–245. doi: 10.5962/bhl.title.49183 . Retrieved 6 June 2023.
  15. ↑ da Graça, W. J.; Oliveira, C. A. M.; Lima, F. C. T.; da Silva, H. P.; Fernandes, I. M. (October 2017). "A new species of Astyanax (Characiformes: Characidae) from Dolina Água Milagrosa, Rio Paraguai basin, Mato Grosso, Brazil: a new astyanax from rio paraguai basin". Journal of Fish Biology. 91 (4): 1123–1138. doi:10.1111/jfb.13405. PMID   28868674.
  16. ↑ Bertaco, Vinicius A.; Lucinda, Paulo H. F. (September 2005). "Astyanax elachylepis, a new characid fish from the rio Tocantins drainage, Brazil (Teleostei: Characidae)". Neotropical Ichthyology. 3 (3): 389–394. doi: 10.1590/S1679-62252005000300006 .
  17. ↑ Garutti, Valdener (1998). "Descrição de Uma Espécie Nova de Astyanax (Teleostei, Characidae) da Bacia do Tocantins, Brasil" [Description Of A New Species Of Astyanax (Teleostei, Characidae) From Tocantins Basin]. Iheringia (in Portuguese). 85. Pôrto Alegre: Museu Rio-Grandense de Ciências Naturais: 121. Retrieved 6 June 2023.
  18. ↑ Costa, Wilson J.E.M. (1995). "Description of a new species of the genus Astyanax (Characiformes: Characidae) from the rio Araguaia basin, Brazil". Revue suisse de zoologie. 102: 257–262. doi: 10.5962/bhl.part.80464 . Retrieved 6 June 2023.
  19. ↑ 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): 72. doi:10.1206/0003-0090.431.1.1. S2CID   196645665 . Retrieved 6 June 2023.
  20. ↑ Froese, Rainer; Pauly, Daniel (eds.) (2023). "Astyanax bourgeti" in FishBase . June 2023 version.
  21. ↑ Ianniruberto, Marco; Trevethan, Mark; Pinheiro, Arthur; Andrade, Joao Fernando; Dantas, Elton; Filizola, Naziano; Santos, André; Gualtieri, Carlo (January 2018). "A field study of the confluence between Negro and Solimões Rivers. Part 2: Bed morphology and stratigraphy". Comptes Rendus Geoscience. 350 (1–2): 43–54. doi:10.1016/j.crte.2017.10.005.
  22. ↑ Administrator, NASA Content (7 August 2017). "Solimões and Negro Rivers". www.nasa.gov. National Aeronautics and Space Administration. Retrieved 6 June 2023.
  23. ↑ Centre, UNESCO World Heritage. "Central Amazon Conservation Complex". whc.unesco.org. UNESCO World Heritage Centre. Retrieved 6 June 2023.
  24. ↑ "Central Amazon Conservation Complex | World Heritage Outlook". worldheritageoutlook.iucn.org. IUCN World Heritage Outlook. Retrieved 6 June 2023.
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