Astyanax bimaculatus

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Twospot astyanax
Astyanax bimaculatus (45778390).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Astyanax
Species:
A. bimaculatus
Binomial name
Astyanax bimaculatus
Linnaeus, 1758
Synonyms [2] [3]

Astyanax bimaculatus borealis(Eigenmann, 1908)
Astyanax bimaculatus incaicus(Tortonese, 1942)
Astyanax fasciatus bimaculatus(Linnaeus, 1758)
Poecilurichthys brevoortii(Gill, 1858)
Salmo bimaculatus(Linnaeus, 1758)
Tetragonopterus bahiensis(Steindachner, 1877)
Tetragonopterus bartlettii(Günther, 1866)
Tetragonopterus gronovii(Valenciennes, 1850)
Tetragonopterus linnaei(Valenciennes, 1850)
Tetragonopterus maculatus(Müller & Troschel, 1845)
Tetragonopterus orientalis(Cope, 1870)
Tetragonopterus vittatus(Castelnau, 1855)
Tetragonopterus wappi(Valenciennes, 1850)

Contents

The twospot astyanax (Astyanax bimaculatus), [2] [4] 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.

Its very earliest report was by prolific taxonomist Carl Linnaeus in 1758, in the 10th edition of Systema Naturae. Linnaeus designated it a member of genus Salmo , and since then it has also been considered a member of the genus Tetragonopterus before being placed in Astyanax. Currently, A. bimaculatus is at the center of a species complex, and specific species relationships are still being deciphered in modern ichthyological studies. As it stands, no monophyly can be guaranteed from A. bimaculatus.

Astyanax bimaculatus is omnivorous, eating plants, zooplankton, and various forms of detritus. It is also known to occasionally target other fish to eat their scales. In turn, A. bimaculatus is regularly preyed upon by Hoplias malabaricus , the trahira, as well as various heron species (genus Ardea ). It is also host to a variety of parasites, most often flukes (Monogenea). Further, A. bimaculatus is a farmed fish for human use, such as consumption or bait.

Taxonomy

When first described by Carl Linnaeus in 1758, A. bimaculatus was given the name Salmo bimaculatus. [5] [6] Throughout the 1800s, various species were named under the genus Tetragonopterus , all of which were later found to be synonymous with A. bimaculatus. [2] [3] In 1912, A. bimaculatus was momentarily considered a species of genus Poecilurichthys. [7] [8] The species Tetragonopterus caudomaculatus, today known as Bryconops caudomaculatus , [9] was once mistakenly identified as being a possible synonym or otherwise close relative. [10]

Astyanax bimaculatus is at the center of a species complex and species subgroup bearing its name. The subgroup in question is made up of at least 20 species, all of which are characterized by various morphological similarities. [11] These species include - but are not limited to - A. argyrimarginatus, A. clavitaeniatus, A. goyacensis, A. novae, A. rupununi, A. saltor, A. siapae, A. unitaeniatus, A. utiariti, A. validus, A. abramis, A. maculisquamis, A. borealis, and A. orbignyanus. [12] In past studies of species in this group, it has been simpler for researchers to ignore designations and consider all examined specimens to be examples of A. bimaculatus, delineating by region instead of name. [11]

Genetics

In terms of genetic information, A. bimaculatus is a notably variable species. Chromosomal study reveals a distinct - and complex - cytotype, or arrangement and number of chromosomes, for populations in different regions. [11] [13] Genetic diversity in the species is not lowered by the presence of waterfalls or dams that separate different populations. [14] An interesting factor in the chromosomal makeup of A. bimaculatus, specifically populations in the Amazon region, is the presence of a B microchromosome, a particularly small type of chromosome present in some birds, reptiles, and fish; [13] little is known regarding the origin and evolution of B microchomosomes. [15]

In genetic studies, many animals are diploid, which means that chromosomes arrange themselves in pairs. When the variable "n" represents chromosome sets, then a diploid animal's chromosome number is represented by "2n". For A. bimaculatus, which is indeed diploid, this number is 2n=50. [16] (To compare, this number is 2n=46 in humans.) The chromosome number 2n=50 is shared by various other species in the A. bimaculatus complex, such as A. lacustris, A. altiparanae, A. asuncionensis, and A. jacuhiensis. [17]

Etymology

The genus name Astyanax originates in the Iliad, originating from the son of prince Hector, the Trojan warrior Astyanax. The specific reason for this allusion was not made clear in the nominal text, but the large, armor-like scales of type species Astyanax argentatus may be responsible. The specific name bimaculatus means "two-spotted", in reference to the distinct pair of markings - the humeral spot and the spot on the caudal peduncle. [18] These two spots also earn A. bimaculatus the common name "twospot astyanax". [19]

Description

Astyanax bimaculatus reaches a maximum total length of 17.5 cm (6.9 in), and a maximum weight of 91.6 g (3.23 oz). [2] The scales are large, and lack distinct radii originating from a single point in the center of each; the presence of such lines was a trait once ascribed to A. bimaculatus, [20] but has since been recognized as a trait of congener A. abramis instead. [21] There are 33 lateral-line scales, 26–27 dorsal-fin rays, and 26–30 anal-fin rays. [22] [23] Before taxonomic revisions, the reported variation in the numbers of fin-rays and lateral-line scales was much greater, due to separate species all being grouped under a single name. [8] [24]

The back is dark-green, the sides a silver-yellow, and there is a clear silver lateral stripe. The base of the dorsal fin and the upper lobe of the caudal fin may be strongly red, pink, or yellow, with reduced coloration in the rest of the fin. [25] There is a strong black humeral spot, and another strong blotch of pigment at the base of the caudal fin that extends onto the middle caudal-fin rays; these two spots are shared amongst all members of the A. bimaculatus species complex, which is often considered one of the defining characteristics therein, even if a small handful of species do not conform, including A. elachylepis and A. varzeae. [26] Markings also characteristic of this complex include two brown vertical bars in the humeral region. [27]

Sexual dimorphism

Female specimens of A. bimaculatus are larger than males. [28] Bony hooks also develop on the anal and pelvic fins of sexually mature males during spawning season, then regress afterwards. [29]

Ecology

Diet

Detail of face and jaw. Astyanax bimaculatus (45778466).jpg
Detail of face and jaw.

Astyanax bimaculatus is an omnivorous fish with a leaning towards plant matter. Roughly 60% of the diet is vegetal in nature, and 40% of animals; of these, dicots are the most prevalent in plants, and insects the most prevalent in animals. [30] However, when presented with a shortage of food, A. bimaculatus is remarkably capable of changing its dietary composition. [31] As a further demonstration of adaptability, A. bimaculatus has been recorded following around another fish species - namely Corydoras polystictus - to take advantage of the invertebrates, detritus, and algae that C. polystictus flushes out during its foraging activity. [32]

Because it mostly eats plant matter, it serves an important role in the food chain, transferring that energy up into the animals that prey upon it. This role also allows it to transmit disease to its predators. [33]

Distribution

Astyanax bimaculatus has an enormous distribution. The rivers and basins it can be found in include, but are not limited to: the Amazonas estuaries and the main channel, Apure, Araguaia, Atrato, Beni-Madre de Dios, Branco, Cauca-Magdalena-Sinu, Coppename, Suriname, Saramacca, Corentyne-Demerara, Essequibo, Guapore, Itapicuru-Mearim, lapura, middle-lower Madeira, Mamore, Maroni-Approuague, Oiapoque, Orinoco (upper and lower), Parnaiba, Purus, Putumayo, upper Tocantins, Ucayali, and upper Xingu. [34]

Though considered sedentary, A. bimaculatus (and members of its species complex) can undertake short-distance migrations if necessary. [35]

Habitat

Because of its remarkable range, A. bimaculatus is tolerant of a wide range of conditions. However, it remains entirely potamodromous (freshwater), and seems to have a preference for water with a pH of 5.5–7.5. [2] Nonetheless, it can stay alive for long periods of time in suboptimal conditions; one example, documented by zoologist William Beebe in 1942, was a wide variety of aquatic life stranded in a pond that had been reduced to a mud puddle in the severe dry season of Caripito, Venezuela. Of 32 A. bimaculatus individuals trapped therein, 12 remained alive in surroundings that should not have sustained them for as long as had already been endured. [25]

Sympatric species

The native range of A. bimaculatus ensures that it will overlap with a great deal of other aquatic species. Its relatively peaceful nature means that it can often coexist without incident, and its dietary flexibility means that ecological competition is unnecessary; if one food item is scarce, it can simply shift targets. As such, environments with high species diversity are not of issue for A. bimaculatus. [31]

One of the most comprehensive lists of species found alongside A. bimaculatus came as a result of William Beebe's discovery of a drying-up pond in Venezuela. Fascinated by the circumstances and by just how many animals had remained alive in such poor conditions, Beebe made an annotated list of all of the species he and his colleagues could identify. Fish species found therein with A. bimaculatus include, but are certainly not limited to: Ochmacanthus flabelliferus, Callichthys callichthys, Hoplosternum littorale, Farlowella acus, Copella arnoldi, Creagrutus beni, Erythrinus erythrinus, Gephyrocharax valencia, Hoplerythrinus unitaeniatus, Pristella maxillaris , and Serrasalmus eigenmanni. Also in the same location were Pipa pipa, the common Surinam toad, and Rhinoclemmys punctularia, the spot-legged wood turtle. [25]

Astyanax bimaculatus has further been collected at turbid-water sites that host Crenicichla britskii, Aphyocheirodon hemigrammus, Hemigrammus marginatus, Hyphessobrycon eques, Gymnocorymbus thayeri, Ctenobrycon hauxwellianus, and Pyrrhulina vittata. [36] [37]

Parasites

Astyanax bimaculatus is a host to various parasites that colonize different parts of the body. Creptotrema dissimilis is a species of trematode (flatworm) that inhabits the intestines. Magnivitellinum simplex, another intestinal trematode, was first described from A. bimaculatus in Brazil. [38] Parasitic isopod Livoneca lazzari was also first described from A. bimaculatus, this time from the gill cavity. [39] The parasites most likely to infect A. bimaculatus come from Monogenea, a class of parasitic flatworms, and infections are more common during the rainy seasons. [40]

Eukaryotic microparasites of the genus Myxobolus have been found inhabiting the gill filaments of A. bimaculatus, but the disease it causes is asymptomatic for A. bimaculatus. [41]

Biology

Astyanax bimaculatus can reach up to 18 years of age. [2]

Reproduction

Astyanax bimaculatus is capable of year-round reproduction, though they are less likely to be in an active reproductive or maturation state during May, June, and July. In times of scarcity, energy resources can be diverted from the bodily fat or from the liver to the gonads of female specimens; males do not use the same strategy. [42] Males also demonstrate reproductive morphology considered to be more "primitive" in phylogeny, including how the sperm cells are formed and carried. [43] The peak of the spawning period, while it may depend on location, has been recorded in January and February. [44]

Female specimens exposed to a chemical signal called "conspecific alarm substance", released by other A. bimaculatus in stressful situations like a predator attack, ovulate earlier than those not exposed - but they only ovulate once, and the generated zygotes may not develop. [45] In normal spawning conditions, larger females can lay larger numbers of eggs, simply because they have more space to carry them. [44] The eggs of A. bimaculatus are weakly adhesive, and are laid in environments of low current. [46]

Spawning has been achieved in captivity. [47]

Role as bioindicator

Wastewater, animal pollutants, and pesticides can all have a negative impact on a given aquatic environment. Specifically, these factors may be genotoxic, which means that they can damage cell "building blocks" and lead to harmful mutations (such as cancer). A. bimaculatus can be used as a biological indicator (bioindicator) of pollutants that may be genotoxic, based upon the formation of micronuclei in the red blood cells. [48] The presence of a micronucleus results from a chromosome (or chromosome fragment) that is not carried into one of the nuclei that forms during cell division, essentially being "left behind"; this is a sign of genotoxicity.

Enzymes from kidney, gill and brain tissues of A. bimaculatus can also be tested to measure environmental impact. The enzymes that are higher or lower depend on factors from the surrounding environment, such as low oxygen, so measurements therein can indicate changes in water parameters and various pollutants. [49]

Behavior

Astyanax bimaculatus is generally non-competitive and will make changes in its own behavior so that its niche is not interfered with by sympatric species; this includes environment usage and components of dietary intake. [50] Generally, it swims in schools, which increases survival for many animal species that live in groups. Laboratory testing has introduced a caveat to this, however. It displays conspecific aggression when faced with the threat of an active, chasing predator. Because predators are known to target the weakest or most isolated of a group, purposefully wounding a group member gives the predator in question an easy target, which increases the survival chances of the others. [51]

Presence and behavior in aquaria

Astyanax bimaculatus is kept in captivity both by hobbyists and by scientists. In hobbyist circles, A. bimaculatus is a species known to need ample swimming space, and should not be paired with more retiring fish given its "rambunctious" habits. [52] Generally, however, it is non-aggressive. [53]

Researchers have experimented with using lactic acid bacteria from the intestinal tract of A. bimaculatus as a probiotic supplement for captive fish. Preliminary laboratory results are promising. [54] In turn, turmeric ( Curcuma longa ) has been shown to have positive histological effects on A. bimaculatus, resulting in decreased parasite activity. [55] Various anesthetics have been tested for efficacy on A. bimaculatus, which can help reduce stress levels during aquacultural procedures in captivity. An organic compound called 2‐phenoxyethanol, as well as the essential oils of tea trees ( Melaleuca alternifolia ) and African basil ( Ocimum gratissimum ), have all proven effective on captive specimens; such results can be used to inform similar tests on other captive fish to ensure welfare. [56]

Conservation status

Astyanax bimaculatus has been evaluated by the IUCN Red List as "Least Concern". [1] There is almost no risk of it becoming endangered, as it is remarkably widespread and incredibly adaptable. The construction of hydroelectric dams in its native range, for example, has not depressed population numbers; in one study, populations from above and below a dam simply developed different morphological properties to cope with the changes in flow, environment, and food availability. [57] Changes in accessible dietary components also do not impede A. bimaculatus populations, as they are prepared to take advantage of whatever food sources may be nearby, given opportunistic feeding habits. [31]

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>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.

<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.

<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.

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

The tailspot tetra 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 at its longest. Despite its small size, it is an active swimmer, with a preference for fast-flowing waters.

<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 munduruku is a small freshwater fish of the family Iguanodectidae that lives in the rivers of South America. Its adipose fin is black, with a clear base, and it has two humeral spots, which is a feature it shares with few congeners. Its fins are a variety of yellow, red, black, and clear, and mature males have hooks on select fin-rays.

<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 altiparanae</i> Species of fish

Astyanax altiparanae, sometimes called the yellow-tail tetra or yellow-tail lambari, is a species of schooling freshwater fish widely distributed across the southern half of South America. It is an ecologically flexible species, able to adapt to various resource and space conditions, and its diet follows this pattern; it is considered opportunistic and omnivorous. Its widespread nature and unspecified ecology contribute to its status as a species of least concern on the IUCN Red List. It was originally described from the upper Paraná river basin, which is the origin of its specific epithet; "alto" means "higher" in Brazilian Portuguese, hence "alto Paraná".

<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 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 biotae</i> Species of fish

Astyanax biotae is a small species of freshwater fish native to various localities in Brazil. It primarily eats invertebrates, like copepods and aquatic fly larvae, and its diet also includes seeds, fruits, and filamentous algae. Its scales are largely silver, with a touch of yellow-brown on the back and a hint of blue on the sides. Like many species of Astyanax, it has a humeral spot, which is a blotch of pigmentation in the area above or around the pectoral fin.

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

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.

<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 brevimanus</i> Species of fish

Astyanax brevimanus, sometimes referred to as the Quiché tetra, is a small species of freshwater fish native to various locales in Guatemala. Its native range is somewhat restricted, but it is a populous and adaptable species, so there is no risk of it going extinct anytime soon. It is unknown what A. brevimanus eats, or what specific habitats it prefers; current information is largely in the form of physical descriptions, general areas of occurrence, and hypotheses regarding relationships to congeners. Its silvery scales, indistinct humeral (shoulder) spot, and dark caudal-peduncle spot are features not unusual in species of Astyanax.

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.

References

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  2. 1 2 3 4 5 6 Froese, Rainer; Pauly, Daniel (eds.) (2023). "Astyanax bimaculatus" in FishBase. May 2023 version.
  3. 1 2 Bailly, Nicolas (2017). "Astyanax bimaculatus (Linnaeus, 1758)". WoRMS. World Register of Marine Species . Retrieved 30 May 2023.
  4. ↑ "Astyanax bimaculatus (Linnaeus, 1758)". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 30 May 2023.
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  6. ↑ "Salmo bimaculatus". Global Biodiversity Information Facility .
  7. ↑ Eigenmann, Carl H. (1912). 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. Pittsburgh: Carnegie Institute. pp. 359–361. doi:10.5962/bhl.title.4686.
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  9. ↑ "Bryconops caudomaculatus". Global Biodiversity Information Facility .
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  12. ↑ "Astyanax lacustris Lutken 1875 - Plazi TreatmentBank". treatment.plazi.org. Retrieved 2023-05-31.
  13. 1 2 Corrêa de Sousa, Rodrigo Petry; dos Santos, Jaymeson Lielson Anjos; Silva-Oliveira, Gláucia Caroline; Furo, Ivanete de Oliveira; de Oliveira, Edivaldo Herculano Corrêa; Vallinoto, Marcelo (February 2023). "Characterization of a new cytotype and ocurrence [sic] of a B microchromosome in two spot astyanax, Astyanax bimaculatus Linnaeus, 1758 (Characiformes: Characidae)". Journal of Fish Biology. 102 (2): 520–524. doi:10.1111/jfb.15265. ISSN   0022-1112. PMID   36321966. S2CID   253257950.
  14. ↑ Paiva, Samuel Rezende; Dergam, Jorge Abdala; Machado, Flávia (May 2006). "Determining Management Units in Southeastern Brazil: The Case of Astyanax bimaculatus (Linnaeus, 1758) (Teleostei: Ostariophysi: Characidae)". Hydrobiologia. 560 (1): 393–404. doi:10.1007/s10750-005-9415-1. ISSN   0018-8158. S2CID   31788551.
  15. ↑ Sampaio, Tatiane R.; Gouveia, Juceli G.; da Silva, Carlos R.M.; Dias, Ana L.; da Rosa, Renata (2015). "Molecular Analysis of the B Microchromosome in Steindachnerina insculpta (Characiformes: Curimatidae) by Microdissection". Cytogenetic and Genome Research. 146 (1): 51–57. doi:10.1159/000381932. ISSN   1424-8581. PMID   25999244. S2CID   41652675.
  16. ↑ Fava, Lucioni (28 March 2008). Variação cariotípica de Astyanax bimaculatus (Linnaeus, 1758) (Pisces: Characidae) nas bacias costeiras do Brasil (Master's thesis) (in Portuguese). Universidade Federal de Viçosa. S2CID   201212813.
  17. ↑ Gavazzoni, Mariane; Paiz, Leonardo M.; Oliveira, Carlos A. M.; Pavanelli, Carla S.; Graça, Weferson J.; Margarido, Vladimir P. (August 2018). "Morphologically Cryptic Species of the Astyanax bimaculatus "Caudal Peduncle Spot" Subgroup Diagnosed Through Cytogenetic Characters". Zebrafish. 15 (4): 382–388. doi:10.1089/zeb.2018.1574. ISSN   1545-8547. PMID   29634423.
  18. ↑ Scharpf, Christopher; Lazara, Kenneth J. (15 April 2024). "Family CHARACIDAE: Subfamily STETHAPRIONINAE Eigenmann 1907 (American Tetras)". The ETYFish Project. Retrieved 6 May 2024.
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  23. ↑ Pamponet, Vanessa de Carvalho Cayres; Carneiro, Paulo Luiz Souza; Affonso, Paulo Roberto Antunes de Mello; Miranda, Viviam Souto; Silva Júnior, Juvenal Cordeiro; Oliveira, Claudine Gonçalves de; Gaiotto, Fernanda Amato (December 2008). "A multi-approach analysis of the genetic diversity in populations of Astyanax aff. bimaculatus Linnaeus, 1758 (Teleostei: Characidae) from Northeastern Brazil". Neotropical Ichthyology. 6 (4): 621–630. doi: 10.1590/S1679-62252008000400010 . ISSN   1679-6225.
  24. ↑ Eigenmann, Carl H. (July 1907). "On further collections of fishes from Paraguay". Annals of the Carnegie Museum. 4 (2): 110–157. doi: 10.5962/p.264300 . ISSN   0097-4463. S2CID   90032154.
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  26. ↑ 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 (2016-12-19). Rétaux, Sylvie (ed.). "Highlighting Astyanax Species Diversity through DNA Barcoding". PLOS ONE. 11 (12): e0167203. Bibcode:2016PLoSO..1167203R. doi: 10.1371/journal.pone.0167203 . ISSN   1932-6203. PMC   5167228 . PMID   27992537.
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  28. ↑ Trujillo Jiménez, Patricia; Sedeño Díaz, Jacinto Elias; Camargo, Julio A.; López López, Eugenia (2013-07-24). "Reproductive traits and population structure of <i>Astyanax aeneus</i> (Characiformes: Characidae) from a subtropical river in Mexico". Revista de Biología Tropical. 61 (2): 769–786. doi: 10.15517/rbt.v61i2.11221 . ISSN   2215-2075. PMID   23885588.
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  31. 1 2 3 Lobón-Cerviá, Javier; Bennemann, Sirlei (2000-09-29). "Temporal trophic shifts and feeding diversity in two sympatric, neotropical, omnivorous fishes: Astyanax bimaculatus and Pimelodus maculatus in Rio Tibagi (Paraná, Southern Brazil)". Fundamental and Applied Limnology. 149 (2): 285–306. doi:10.1127/archiv-hydrobiol/149/2000/285. ISSN   1863-9135.
  32. ↑ Leitão, Rafael P.; Caramaschi, Érica P.; Zuanon, Jansen (September 2007). "Following food clouds: feeding association between a minute loricariid and a characidiin species in an Atlantic Forest stream, Southeastern Brazil". Neotropical Ichthyology. 5 (3): 307–310. doi: 10.1590/S1679-62252007000300011 . ISSN   1679-6225.
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  37. ↑ Kullander, Sven O. (1976). "Apistogramma luelingi sp. nov., a new Cichlid Fish from Bolivia (Teleostei: Cichlidae)". Bonner zoologische Beiträge. 27–28: 263. Retrieved 30 May 2023– via BHL.
  38. ↑ Ostrowski de Núñez, M.; Arredondo, N.J.; Gil de Pertierra, A.A. (2017-03-22). "Adult Trematodes (Platyhelminthes) Of Freshwater Fishes From Argentina: A Checklist". Revue suisse de Zoologie. 124. doi:10.5281/ZENODO.322669.
  39. ↑ Pearse, A. S. (1921). "Crustacea from Lake Valencia, Venezuela". Proceedings of the United States National Museum. 59 (2381): 459–462. doi:10.5479/si.00963801.59-2381.459. hdl:10088/15161.
  40. ↑ Antunes, Dhenes Ferreira; Anderson Fernandes Silva, Bruno; Yamada, Fabio Hideki (October 2022). "Effect of parasitism on the relative condition factor of Astyanax bimaculatus (Characiformes: Characidae) a freshwater fish from Caatinga domain, Brazil". International Journal of Aquatic Biology. 10 (5). Retrieved 30 May 2023.
  41. ↑ Silva, Marcelo Francisco da; Sousa-Henrique, Dalila de Deus; Messias-Luz, Nirvana; Borralho, Larissa dos Santos; Oliveira, Jorge Diniz de; Sindeaux-Neto, José Ledamir; Matos, Edilson Rodrigues (December 2019). "Myxobolus sp. (Myxozoa; Myxosporea) causing asymptomatic parasitic gill disease in Astyanax aff. bimaculatus (Characiformes; Characidae) in the Tocantins river basin, amazon region, Brazil". Revista Brasileira de Parasitologia Veterinária. 28 (4): 739–743. doi: 10.1590/s1984-29612019041 . ISSN   1984-2961. PMID   31390431. S2CID   199503949.
  42. ↑ Pellucci Barreto, Bianca (1998). "Biologia reprodutiva do lambarí Astyanax bimaculatus (Pisces, Characidae) no rio do Carmo, bacia do rio Grande, São Paulo". BIOS. 6 (6): 121–130.
  43. ↑ Cordeiro, Jhennifer Gomes; Rodrigues, Jeane; Rodrigues, Maira da Silva; Bertolini, Rafaela Manchin; Nóbrega, Rafael Henrique; Yasui, George Shigueki; Maximino, Caio; Siqueira-Silva, Diógenes Henrique de (February 2020). "Reproductive cycle of the tetra Astyanax bimaculatus (Characiformes: Characidae) collected in Amazonian streams". Zygote. 28 (1): 37–44. doi:10.1017/S0967199419000601. ISSN   0967-1994. PMID   31603066. S2CID   204243383.
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  45. ↑ Rodrigues, Jeane; Rosa-Silva, Maria; Tercya, Hadda; Jesus, Paulo; Miranda, Saynara; Oliveira, Hingrid; Lima, Bianca; Santos, Ludmylla; Maximino, Caio; Siqueira-Silva, Diógenes (June 2023). "Oogenesis and in vitro reproduction of the twospot astyanax Astyanax bimaculatus (Linnaeus, 1758) exposed to conspecific alarm substance". Animal Reproduction Science. 253: 107252. doi:10.1016/j.anireprosci.2023.107252. PMID   37209522. S2CID   258531761.
  46. ↑ Weber, André Alberto; Arantes, Fábio Pereira; Sato, Yoshimi; Rizzo, Elizete; Bazzoli, Nilo (May 2013). "Oocyte adhesiveness and embryonic development of Astyanax bimaculatus (Linnaeus, 1758) (Pisces: Characidae)". Zygote. 21 (2): 198–202. doi:10.1017/S096719941200007X. ISSN   0967-1994. PMID   22717095. S2CID   22097917.
  47. ↑ Marcon, Lucas; Freitas, Vivian Rocha; Bazzoli, Nilo; Rizzo, Elizete; Benjamin, Laércio dos Anjos (2019). "Growth hormone on ovarian morphology of lambaris (Astyanax bimaculatus) after induced spawning". Ciência Rural. 49 (8). doi:10.1590/0103-8478cr20180478. ISSN   1678-4596. S2CID   201209252.
  48. ↑ Bogoni, Juliano André; Armiliato, Neide; Araldi-Favassa, Celi Teresinha; Techio, Vânia Helena (April 2014). "Genotoxicity in Astyanax bimaculatus (Twospot Astyanax) Exposed to the Waters of Engano River (Brazil) as Determined by Micronucleus Tests in Erythrocytes". Archives of Environmental Contamination and Toxicology. 66 (3): 441–449. doi:10.1007/s00244-013-9990-5. ISSN   0090-4341. PMID   24435477. S2CID   2159580.
  49. ↑ Batista, Maria Tereza Oliveira; Almeida, Marilia Elias de; Vani, Gannabathula Sree; Oliveira, Mariana Feijó de; Rodrigues, Edson; Suda, Cecilia Nahomi Kawagoe (2019-12-26). "Enzymes from kidney, gill and brain tissues of Astyanax bimaculatus (lambari) as biomarkers of environmental impact in the Una River basin". Ambiente e Agua. 14 (7): 1. doi: 10.4136/ambi-agua.2314 . ISSN   1980-993X. S2CID   216653632.
  50. ↑ Arcifa, Marlene Sofia; Northcote, Thomas Gordon; Froehlich, Otávio (May 1991). "Interactive ecology of two cohabiting characin fishes ( Astyanax fasciatus and Astyanax bimaculatus ) in an eutrophic Brazilian reservoir". Journal of Tropical Ecology. 7 (2): 257–268. doi:10.1017/S0266467400005423. ISSN   0266-4674. S2CID   85840030.
  51. ↑ Goulart, Vinícius D.L. R.; Young, Robert J. (August 2013). "Selfish behaviour as an antipredator response in schooling fish?". Animal Behaviour. 86 (2): 443–450. doi:10.1016/j.anbehav.2013.05.041. S2CID   53169631.
  52. ↑ "Astyanax bimaculatus – Two Spot Astyanax — Seriously Fish" . Retrieved 2023-05-31.
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  55. ↑ de Moraes França Ferreira, Pollyanna; Martins, Maria Tatiana Soares; Caldas, Débora Werneck; Gomes, Juliana Rodrigues; de Oliveira, Jerusa Maria; Salaro, Ana Lucia; Rocha, Juliana Silva; Zuanon, Jener Alexandre Sampaio (June 2017). "Curcuma longa as additive in the diet for Astyanax aff. bimaculatus". Fish Physiology and Biochemistry. 43 (3): 691–702. doi:10.1007/s10695-016-0325-0. ISSN   0920-1742. PMID   28083736. S2CID   254505932.
  56. ↑ Silva, Eduardo; Aldegunde, Manuel; Silva, Deivisson Ferreira; Lopes, Carlize; Bertoldi, Fabiano Cleber; Weber, Robilson Antônio (February 2020). "Assessment of induction and recovery times of anaesthesia in Astyanax bimaculatus using 2-phenoxyethanol and the essential oils of Melaleuca alternifolia and Ocimum gratissimum". Aquaculture Research. 51 (2): 577–583. doi: 10.1111/are.14404 . ISSN   1355-557X. S2CID   213200473.
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