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.[1]
| Astyanax aramburui | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Characiformes |
| Family: | Characidae |
| Genus: | Astyanax |
| Species: | A. aramburui
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| Binomial name | |
| Astyanax aramburui Protogino, Miquelarena & López, 2006
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Its taxonomy faces some mild debate, but this is not unusual regarding Astyanax as a genus; further, it can be differentiated from various similar congeners by way of several distinctive features. The most notable of these is the presence of small protrusions on the head and scales of sexually mature male specimens, which only have a limited presence in other members of the genus Astyanax. Otherwise, its scales are silver with a touch of yellow, and it has a single black humeral spot. Little has been published about its physiology or feeding habits.
Taxonomy
editAstyanax aramburui was first described in 2006 from the Parana and Uruguay river basins by a trio of Argentinian scientists.[2] There are three subgenera currently recognised in Astyanax - Astyanax, Poecilurichthys, and Zygogaster[3] - but it has not been determined to which A. aramburui belongs.
It was momentarily suggested in 2010 that A. aramburui be designated a junior synonym of congener A. rutilus, (before reclassification as Psalidodon rutilus), but both species are still considered valid given numerous morphological and genetic differences.[4] On the other hand, there is genetic evidence to suggest that other currently cryptic species of Astyanax may in fact be junior synonyms of A. aramburui, but research is ongoing.[5] For example, specimens of Astyanax aff. fasciatus collected from Argentina may have been incorrectly identified.[6] This continued confusion has led scientists to suggest further revision of the relevant taxonomy.[7]
Etymology
editThe genus name "Astyanax" originates in Homer's Iliad. Astyanax was a Trojan warrior, and the son of Trojan prince Hector; the reason for the allusion possibly lies in the scales of type species Astyanax argentatus, which are large and armor-like. ("Argentatus" means "silver").[8] The specific epithet "aramburui" is an allusion to ichthyologist Raúl Arámburu, who founded the first chair of ichthyology in Argentina;[9] this is particularly pertinent because A. aramburui is endemic to the country.[8]
In terms of a common name, A. aramburui is one of various small fish species referred to as "Mojarra" in South America.[1] Otherwise, no common names are in wide use by the scientific community.[10]
Description
editAstyanax aramburui reaches a maximum of 6.1 cm (2.4 in) SL (standard length).[11] The body is slender, as is the caudal joint, and the head has a short snout and large eye.[2] The maxillary bears a single tooth.[12] The lateral line has 38 to 42 scales, which is a feature that can be used to distinguish A. aramburui from similar congeners.[13] A round or trapezoidal black humeral spot is present above the lateral line.[11] This also can be used to differentiate it from species such as Astyanax powelli, which has two humeral spots in opposition to just one in A. aramburui.[12]
The scales are mostly an iridescent silver with touches of yellow, and there is a scattering of dark color cells (chromatophores) on top of the head and body. The sides of the head and the lateral stripe are both plain silver, ending in a black spot on the caudal peduncle. This spot spreads onto the caudal fin itself, which is largely gray with a darker margin. The first rays of the pectoral fins are dark, but the rest of the fin is hyaline (clear), and the pelvic fin is solely hyaline. The dorsal and anal fins bear scattered black color cells.[14]
Sexual dimorphism
editMature males of A. aramburui bear bony hooks on all fins.[12] Further, males have small protrusions known as "epidermal breeding tubercles" on a notable proportion of the head and scales, which is unusual in Astyanax and can be used as a characterizing feature of the species.[2] Otherwise, there are no morphometric or coloration differences.
Distribution and ecology
editAstyanax aramburui is endemic to Argentina, originally described from the Paraná and Uruguay river systems.[2] Its type locality is part of a relatively extensive section of river, about 50 metres (164 ft) across at its widest, with substrate consisting of mud and clay.[11] Specific locations from whence it has been cited are the Villaguay Creek and Brazo Chico Creek.[1] The river sub-basin in which both creeks are located, the Gualeguay, has relatively high yearly precipitation, averaging 1,311 mm (52 in).[15]
Little is known regarding A. aramburui's dietary needs, but many members of Astyanax are adaptable omnivores.[16]
Conservation status
editAstyanax aramburui was considered rare in a 2009 study of the threatened fishes of Argentina,[17] and is listed as a near threatened species on the IUCN Red List;[1] Its relatively restricted range plays a part in both classifications. Threats include pollution from tanneries and meat packing plants in the Gualeguay River basin. The basin is also subject to chemical pollution from various pesticides used in local agriculture.[18]
References
edit- ^ a b c d e Liotta, J. (2022). "Astyanax aramburui". IUCN Red List of Threatened Species. 2022: e.T176406033A176406105. doi:10.2305/IUCN.UK.2022-1.RLTS.T176406033A176406105.en. Retrieved 18 April 2023.
- ^ a b c d Protogino, Lucila C.; Miquelarena, Amalia M.; López, Hugo L. (17 August 2006). "A new species of Astyanax (Teleostei, Characiformes, Characidae), with breeding tubercles, from the Paraná and Uruguay river basins". Zootaxa. 1297 (1): 1. doi:10.11646/zootaxa.1297.1.1. hdl:11336/17642.
- ^ 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.
- ^ Camelier, P.; Zanata, A. M. (February 2014). "A new species of Astyanax Baird & Girard (Characiformes: Characidae) from the Rio Paraguaçu basin, Chapada Diamantina, Bahia, Brazil, with comments on bony hooks on all fins: New Astyanax with hooks on all fins of males". Journal of Fish Biology. 84 (2): 475–490. doi:10.1111/jfb.12295. PMID 24446730.
- ^ Mariane, Gavazzoni (2016-02-22). Uma abordagem sistemática em espécies de Astyanax (characiformes, characidae, incertae sedis) da bacia do alto-médio rio Uruguai através da análise citogenética básica e molecular (Master's thesis) (in Portuguese). Universidade Estadual do Oeste do Parana.
- ^ Mirande, Juan Marcos; Koerber, Stefan (2015). "On some species of Astyanax reported erroneously from Argentina". Ichthyological Contributions of PecesCriollos. 35: 1–8. Retrieved 18 April 2023.
- ^ Gavazzoni, Mariane; Pavanelli, Carla S; Graça, Weferson J; Melo, Bruno F; Gubiani, Éder André; Margarido, Vladimir P (28 February 2020). "Detection of natural hybridization and delimitation of two closely related operational taxonomic units of the Astyanax fasciatus (Teleostei: Characidae) complex through integrative approaches". Biological Journal of the Linnean Society. 129 (3): 687–700. doi:10.1093/biolinnean/blz199.
- ^ a b Scharpf, Christopher; Lazara, Kenneth J. (28 December 2023). "Family CHARACIDAE: Subfamily STETHAPRIONINAE Eigenmann 1907 (American Tetras)". The ETYFish Project. Retrieved 29 January 2024.
- ^ Koerber, Stefan (2011). "Freshwater fishes of Argentina: Etymologies of species names dedicated to persons" (PDF). Freshwater Fishes of Argentina: Etymologies of Species Names Dedicated to Persons. 18: 1–18. Retrieved 18 April 2023.
- ^ "Astyanax aramburui Protogino, Miquelarena & López 2006". Encyclopedia of Life. National Museum of Natural History. Retrieved 18 April 2023.
- ^ a b c Froese, Rainer; Pauly, Daniel (eds.). "Astyanax aramburui". FishBase. April 2023 version.
- ^ a b c Terán, Guillermo E.; Butí, Cristina I.; Mirande, J. Marcos (2017). "A new species of Astyanax (Ostariophysi: Characidae) from the headwaters of the arheic Río Sucuma, Catamarca, Northwestern Argentina". Neotropical Ichthyology. 15 (2). doi:10.1590/1982-0224-20160165. hdl:11336/78107.
- ^ Oliveira, Carlos Alexandre Miranda; Oliveira, Anielly Galego de; Pavanelli, Carla Simone (23 March 2018). "Expanding the geographical distribution of Astyanax biotae Castro & Vari, 2004 (Characiformes, Characidae), with comments on its conservation status". Check List. 14 (2): 387–392. doi:10.15560/14.2.387.
- ^ Protogino, Lucila C.; Miquelarena, Amalia M.; López, Hugo L. (31 December 2006). "Astyanax aramburui Protogino, Miquelarena & López, 2006, new species". Zootaxa. 1297: 2–12. doi:10.5281/zenodo.6258680 – via Zenodo.
- ^ Bianchi, Juan; Goniadzki, Dora (June 2012). "Hydrological modelling of the Gualeguay River basin for hydrological forecast and alert using microwave remote sensing information". ResearchGate. Retrieved 18 April 2023.
- ^ Vilella, Fábio Silveira; Becker, Fernando Gertum; Hartz, Sandra Maria (June 2002). "Diet of Astyanax species (Teleostei, Characidae) in an Atlantic Forest River in Southern Brazil". Brazilian Archives of Biology and Technology. 45 (2): 223–232. doi:10.1590/S1516-89132002000200015. hdl:10183/78925.
- ^ "Astyanax aramburui". sib.gob.ar (in Spanish). Sistema de Información de Biodiversidad de la Administración de Parques Nacionales. Retrieved 18 April 2023.
- ^ Mac Loughlin, Tomás M.; Peluso, María Leticia; Marino, Damián J.G. (December 2022). "Evaluation of pesticide pollution in the Gualeguay Basin: An extensive agriculture area in Argentina". Science of the Total Environment. 851 (Pt 1): 158142. doi:10.1016/j.scitotenv.2022.158142. hdl:11336/211312. PMID 35988611. S2CID 251683243.