Astyanax caballeroi

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Astyanax caballeroi
Astyanax caballeroi preserved (1).png
Preserved specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Astyanax
Species:
A. caballeroi
Binomial name
Astyanax caballeroi
Contreras-Balderas & Rivera-Teillery, 1985
Synonyms

Bramocharax caballeroi(Contreras-Balderas & Rivera-Teillery, 1985)

Contents

Astyanax caballeroi is a small species of freshwater fish endemic to a single lake system in Mexico. It has a longer snout and more slender body than most other species in the genus Astyanax, thought to be the result of predatory behavior; while A. caballeroi eats invertebrates and smaller fish, other Astyanax species are more broadly omnivorous, and have deeper bodies with shorter snouts. This difference in body shape once placed A. caballeroi, along with several other species of Astyanax, into the former genus Bramocharax.

Its coloration - a combination of green and silver with black details - is not at all uncommon in species of Astyanax native to Mexico. Its other physical differences, however, allow for easy delineation between related species. For instance, congener Astyanax aeneus is one of the closest relatives of A. caballeroi, despite the disparity in appearance.

Taxonomy

When originally described, A. caballeroi was placed in the now-defunct genus Bramocharax and subgenus Catemaco, known as Bramocharax (Catemaco) caballeroi. [2] [3] Some databases, such as GBIF [4] and the Encyclopedia of Life, [5] still list it under this name. In 2017, Mexican ichthyologist Juan J. Schmitter-Soto redescribed the species as a member of Astyanax; this was the first examination of A. caballeroi in the context of Astyanax rather than Bramocharax, though Bramocharax had already fallen out of use by 2017. [6] Other than its basionym, A. caballeroi has no known synonyms. [7]

Modern ichthyologists largely consider Bramocharax obsolete in favor of Astyanax. Other species formerly in Bramocharax include Astyanax baileyi , Astyanax bransfordii , and Astyanax dorioni . [8] Genetic examination has found that these species are more closely related to other Astyanax species than to each other, indicating that they are a part of Astyanax rather than part of a distinct genus. One 2008 study found that A. caballeroi exhibited genetic similarities to specific populations of Astyanax fasciatus from the Catemaco region of Mexico. [9] (Astyanax fasciatus is also an obsolete name, since split up into multiple other species of Astyanax and several species of Psalidodon .) [10]

The reason for the original differentiation originated in the morphological differences between species. Bramocharax was defined by a long jaw, compressed body, and unicuspid (single-pointed) teeth. Astyanax species are recognizable largely by a deep body, compressed snout, and multicuspid teeth. [11] These differences, however, are now thought to originate in trophic pressures in different regions that necessitated similar adaptations; that is to say, Bramocharax species lived in areas where they faced similar problems, and a more streamlined body shape met those needs more readily than standard Astyanax morphology. If Bramocharax were a legitimate genus, these traits would have been inherited from a shared relationship to a common ancestor. [9] The term "Bramocharax morph" or "Bramocharax-type" is still used to refer to species that have the traits associated with former Bramocharax species. [12]

Astyanax caballeroi is related to congener Astyanax aeneus , with which it lives in sympatry; [12] [13] clear physical characteristics allow for delineation between the two. [14] Despite morphological differences, there is suspicion based upon genetic data that A. caballeroi may be synonymous with A. aeneus, but the possibility exists that they are in the early stages of speciation. [14] [15]

Astyanax caballeroi is known to share elements of its phyletic lineage with congener Astyanax finitimus . [6]

Etymology

The specific epithet "caballeroi" originates in Mexican biologist Eduardo Caballero (1904-1974), whom the original authors (Contreras-Balderas and Rivera-Teillery) described as "distinguished". The genus name "Astyanax", while less clear in origin, is tied to the Iliad, wherein Astyanax was a Trojan warrior and son of prince Hector. Modern etymologists largely agree that this is due to the type specimen, Astyanax argentatus , which has large scales comparable to armor or a shield. Because the allusion was not made clear in the nominal text, however, this is unconfirmed. [16]

Given its type locality, A. caballeroi is sometimes referred to as the Catemaco characin or Catemaco tetra. [4]

Description

Astyanax caballeroi reaches roughly 13.8 cm (5.4 in) SL (standard length, without the tail fin). [17] It is fusiform - slender-bodied - and has a notably longer and more upturned snout in comparison to other Astyanax species; this is thought to relate to diet. [13] A longer snout is characteristic of species formerly assigned to Bramocharax, but A. caballeroi has a somewhat shorter snout than the others of the same morphotype. [18] The upper profile is slightly concave. There are 10 dorsal-fin rays (9 on rare occasions), 24–29 anal-fin rays (most often 25), and 11–16 pectoral-fin rays. The lateral line consists of 33–37 scales, with an average of 35. [6]

The base scale color is a dull-green, more intense ventrally and more silver towards the belly. There is a dark lateral line down each side, and a single humeral spot shaped like the letter P. The original description noted a similarity in coloration to other Astyanax species from Mexico. [18] The lateral stripe meets a spot of dark pigment on the caudal peduncle, which continues onto the rays of the caudal fin; otherwise, the fins are largely unpigmented, though they may be yellow. [6] Before its current accepted assignment to the genus Astyanax, the humeral spot and caudal spot of A. caballeroi drew comparisons to other Astyanax species, in which these are common features. [19]

Juvenile specimens of A. caballeroi have been noted to bear a strong resemblance to juveniles of Astyanax mexicanus , though this is resolved with age. Several similarities between the two species also appear in skull osteology. [19]

Sexual dimorphism

Astyanax caballeroi demonstrates a sexually-dimorphic trait referred to as nuptial tubercles, wherein small, fleshy protrusions appear on the rays of the anal and pelvic fins of mature males. This is a trait not uncommon in Astyanax as a whole, though some species grow bony hooks instead. In A. caballeroi, these tubercles are simple (in one piece), as opposed to bifid (split in two). [18]

Distribution and ecology

Fishing boats docked on the shore of Lake Catemaco. Lake Catemaco12.JPG
Fishing boats docked on the shore of Lake Catemaco.

Astyanax caballeroi is endemic to Lake Catemaco and several surrounding rivers in Veracruz, Mexico. [1] The region is one of the most humid in the country, and has high temperatures, up to 38 °C (100 °F); the lake itself is situated 332 m (1,089 ft) above sea level. [20] A. caballeroi is known to be abundant therein, and has been collected alongside species from the genera Xiphophorus , Poecilia , Dorosoma , and Heterandria . [21]

The diet of A. caballeroi consists largely of invertebrates and detritus from other fish, with supplemental plant material. [22] It is also known to demonstrate piscivory; [13] predatory behavior (of fish and invertebrates) is thought to be responsible for the more slender body and longer snout of former Bramocharax species. [12]

Conservation status

Astyanax caballeroi is considered a data deficient species by the IUCN; more knowledge about distribution and population is needed before a more detailed status can be determined. Currently, known threats include sediment deposition as a result of riparian zone destruction, pollution from nearby human populations, and pollution from agricultural activities. Nonetheless, the population is believed to be stable, and A. caballeroi is known to occur within the protected Los Tuxtlas Biosphere Reserve. [1]

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>Astyanax jordani</i> Species of fish

Astyanax jordani is a freshwater fish of the characin family of order Characiformes, native to Mexico. It is sometimes called the cave tetra, or by its local Spanish name sardina ciega.

<i>Rocio</i> Genus of cichlid fishes

Rocio is a small genus of cichlid freshwater fishes from southern Mexico and northern Central America.

<i>Algansea</i> Genus of fishes

Algansea is a genus of ray-finned fish in the family Leuciscidae, distributed in the Lerma–Chapala–Grande de Santiago, Pátzcuaro, Armería, Ameca, Ayutla and Tuxpan basins in west-central Mexico. The genus includes both species that are locally numerous, and species that are highly threatened. Their closest relative is the longfin dace.

<i>Nosferatu molango</i> Species of fish

Nosferatu molango, also known as Atezca Cichlid, is a species of cichlid endemic to the "Laguna Atezca", in the headwaters of the Rio Moctezuma, in the municipality of Molango, state of Hidalgo, Mexico at 1,270 meters above sea level. It is distinguished from other species of the genus in "having a slender, well-spaced, unicuspid and conical, posterior slightly flattened, indented lower pharyngeal plate, with 2 rows of 8–9 medium-sized, lightly pigmented molars that flank the midline; 11–13 nonenlarged conic teeth along the posterior margin. Distinguished from all other species in the genus by a combination of the following characters: predorsal contour deep and nonacute, which is not concave before the eye; head short, rostral tip to the pectoral fin origin distance ; caudal peduncle short and deep, long anal fin ; wide preorbit ; eye small. Peritoneum is uniformly very dark."

<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 acatlanensis</i> Species of fish

Astyanax acatlanensis, sometimes called the Acatlán tetra, is a small species of fish from the rivers of Mexico. It is a relatively hardy species that is able to tolerate a variety of water conditions, but is only found in freshwater, never brackish or marine. It is known only from the Río Acatlán, which is its type locality, and the Río Jía, which is a small, unknown river in the Oaxaca region.

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

Astyanax aeneus, the banded tetra, is a small species of fish native to southern Central America and northern South America. It can be found in a variety of environments, including lakes, rivers, ponds, and slightly brackish locales like lagoons. As well as a varied habitat, it has a varied omnivorous diet: algae, seeds, leaves, insects, and fish fry appear to be the most common.

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

Astyanax altior, the Yucatán tetra, is a small species of freshwater fish endemic to the Yucatán Peninsula of Mexico. It largely inhabits the cenotes of the region, and can tolerate water of limited salinity, though it largely prefers freshwater. Its diet includes plant matter and invertebrates, and there may be an element of cannibalism involved.

<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 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 bacalarensis</i> Species of fish

Astyanax bacalarensis, sometimes referred to as the Bacalar tetra, is a small species of freshwater fish found in Central and South America. Its scientific and common names both refer to its type locality, Lake Bacalar in Mexico, and it further inhabits freshwater environments like cenotes, streams, and wetlands. Its widespread nature, paired with an omnivorous diet, make it a hardy species.

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

Astyanax baileyi is a small freshwater fish native to northern Guatemala. Based on several visual aspects, it was once considered a member of the genus Bramocharax, which is now obsolete, and has since been synonymized with Astyanax. As such, former members of Bramocharax are now a part of Astyanax, like Astyanax bransfordii and Astyanax caballeroi.

<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.

Astyanax bransfordii, sometimes called the longjaw tetra, is a small carnivorous species of fish endemic to a handful of lakes and slow-moving canals in Central America. Its range includes Lake Nicaragua and Lake Managua, which are two of the largest freshwater bodies in Central America; because it occurs only in the relevant areas of Costa Rica and Nicaragua, the area it actually inhabits is somewhat restricted. Its diet largely consists of various invertebrates and smaller fish. This is in contrast to various other species of Astyanax, which are more often omnivorous.

<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.

References

  1. 1 2 3 Mercado Silva, N. (2019). "Astyanax caballeroi". IUCN Red List of Threatened Species . 2019: e.T191202A1972601. doi: 10.2305/IUCN.UK.2019-2.RLTS.T191202A1972601.en . Retrieved 4 August 2023.
  2. ↑ "Astyanax caballeroi". National Center for Biotechnology Information (NCBI). Retrieved 4 August 2023.
  3. ↑ "Bramocharax (Catemaco) caballeroi Contreras-Balderas & Rivera-Teillery, 1985". www.zoobank.org. International Commission on Zoological Nomenclature. Retrieved 5 August 2023.
  4. 1 2 "Astyanax caballeroi". Global Biodiversity Information Facility . Retrieved 4 August 2023.
  5. ↑ "Bramocharax caballeroi Contreras-Balderas & Rivera-Teillery, 1985". Encyclopedia of Life . National Museum of Natural History . Retrieved 4 August 2023.
  6. 1 2 3 4 Schmitter-Soto, Juan J. (26 June 2017). "A revision of Astyanax (Characiformes: Characidae) in Central and North America, with the description of nine new species". Journal of Natural History. 51 (23–24): 1331–1424. Bibcode:2017JNatH..51.1331S. doi:10.1080/00222933.2017.1324050. S2CID   90642754.
  7. ↑ Bailly, Nicolas (2022-07-13). "Astyanax caballeroi (Contreras-Balderas & Rivera-Teillery, 1985)". WoRMS. World Register of Marine Species . Retrieved 4 August 2023.
  8. ↑ Schmitter-Soto, Juan Jacob (6 May 2016). "A phylogeny of Astyanax (Characiformes: Characidae) in Central and North America". Zootaxa. 4109 (2): 101–130. doi:10.11646/zootaxa.4109.2.1. PMID   27394856.
  9. 1 2 Ornelas-García, Claudia; Domínguez-Domínguez, Omar; Doadrio, Ignacio (2008). "Evolutionary history of the fish genus Astyanax Baird & Girard (1854) (Actinopterygii, Characidae) in Mesoamerica reveals multiple morphological homoplasies". BMC Evolutionary Biology. 8 (1): 340. Bibcode:2008BMCEE...8..340O. doi: 10.1186/1471-2148-8-340 . PMC   2657800 . PMID   19102731.
  10. ↑ Bailly, Nicolas (2021-08-03). "Astyanax fasciatus (Cuvier, 1819)". WoRMS. World Register of Marine Species . Retrieved 4 August 2023.
  11. ↑ Garita-Alvarado, Carlos A.; Ornelas-García, Claudia Patricia (30 August 2021). "Parallel Evolution of Allometric Trajectories of Trophic Morphology between Sympatric Morphs of Mesoamerican Astyanax (Characidae)". Applied Sciences. 11 (17): 8020. doi: 10.3390/app11178020 .
  12. 1 2 3 Powers, Amanda K.; Garita-Alvarado, Carlos A.; Rodiles-Hernández, Rocío; Berning, Daniel J.; Gross, Joshua B.; Ornelas-García, C. Patricia (5 January 2020). "A geographical cline in craniofacial morphology across populations of Mesoamerican lake-dwelling fishes". Journal of Experimental Zoology Part A: Ecological and Integrative Physiology. 333 (3): 171–180. Bibcode:2020JEZA..333..171P. doi:10.1002/jez.2339. PMC   7372644 . PMID   31904195.
  13. 1 2 3 Ornelas-García, Claudia Patricia; Bautista, Amando; Herder, Fabian; Doadrio, Ignacio (22 September 2017). "Functional modularity in lake-dwelling characin fishes of Mexico". PeerJ. 5: e3851. doi: 10.7717/peerj.3851 . PMC   5611896 . PMID   28951817.
  14. 1 2 Ornelas-García, Claudia P.; Bastir, Markus; Doadrio, Ignacio (July 2014). "Morphometric variation between two morphotypes within the Astyanax Baird and Girard, 1854 (Actinopterygii: Characidae) genus, From a Mexican tropical lake: Lacustrine morphs in Astyanax". Journal of Morphology. 275 (7): 721–731. doi:10.1002/jmor.20252. PMID   24470053. S2CID   12663350.
  15. ↑ Ornelas-García, Claudia Patricia; Gonzalez, Elena G.; Tautz, Diethard; Doadrio, Ignacio (3 July 2023). "Lack of genetic differentiation between two sympatric lacustrine morpho-species within the Astyanax (Characidae: Teleostei) genus, Mexico". Ichthyological Research. 71: 95–105. doi: 10.1007/s10228-023-00917-1 . hdl: 10261/331227 .
  16. ↑ Scharpf, Christopher; Lazara, Kenneth J. (28 December 2023). "Family CHARACIDAE: Subfamily STETHAPRIONINAE Eigenmann 1907 (American Tetras)". The ETYFish Project. Retrieved 27 January 2023.
  17. ↑ Froese, Rainer; Pauly, Daniel (eds.) (2023). "Astyanax caballeroi" in FishBase . August 2023 version.
  18. 1 2 3 "Astyanax caballeroi (Contreras-Balderas and Rivera-Teillery 1985) Schmitter-Soto, 2017". treatment.plazi.org. Plazi TreatmentBank. Retrieved 4 August 2023.
  19. 1 2 Valdez–Moreno, Martha Elena; Contreras–Balderas, Salvador (8 October 2008). "Descripción del cráneo de Bramocharax caballeroi Contreras & Rivera 1985 (Pisces, Characidae), pez endémico del Lago de Catemaco, Veracruz, México". Hidrobiológica. 19 (1). Retrieved 5 August 2023.
  20. ↑ Komárková, Jaroslava; Tavera, Rosaluz (2003). "Steady state of phytoplankton assemblage in the tropical Lake Catemaco (Mexico)". Phytoplankton and Equilibrium Concept: The Ecology of Steady-State Assemblages. pp. 187–196. doi:10.1007/978-94-017-2666-5_17. ISBN   978-90-481-6433-2.
  21. ↑ Torres-Orozco B., Roberto E.; Zanatta, Sandra A. (June 1998). "Species composition, abundance and distribution of zooplankton in a tropical eutrophic lake: Lake Catemaco, México". Revista de Biología Tropical. 46 (2): 285–296. ISSN   0034-7744 . Retrieved 5 August 2023.
  22. ↑ Ornelas-García, Claudia Patricia; Córdova-Tapia, Fernando; Zambrano, Luis; Bermúdez-González, María Pamela; Mercado-Silva, Norman; Mendoza-Garfias, Berenit; Bautista, Amando (May 2018). "Trophic specialization and morphological divergence between two sympatric species in Lake Catemaco, Mexico". Ecology and Evolution. 8 (10): 4867–4875. Bibcode:2018EcoEv...8.4867O. doi:10.1002/ece3.4042. PMC   5980260 . PMID   29876065.
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