Iguanodectinae

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Iguanodectinae
Iguanodectes geisleri - AquaPorteDoree.JPG
Iguanodectes geisleri
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Characiformes
Family:
Iguanodectidae
Subfamily:
Iguanodectinae

Eigenmann, 1909

Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes . Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras (Iguanodectes geisleri and Iguanodectes spilurus, respectively). There is minor, but ongoing, debate regarding its taxonomy.

Contents

Description

Members of Iguanodectinae are generally fairly small, none more than 13 cm in length. Members of Piabucus are slightly larger than members of Iguanodectes, reaching a maximum of 12.9 cm (5.1 in), while members of Iguanodectes only reach 10.3 cm (4.1 in). [1] [2] They are slender and rather elongate in body shape, comparable to minnows; ichthyologist Carl H. Eigenmann, who named the subfamily, likened them to smelt. [3] Their scales are often brightly colored or reflective, and this, combined with their small size, makes them a potential target for the aquarium industry. [4]

The dorsal fin is located behind the middle of the body and usually behind the start of the pelvic fin, though sometimes the dorsal and pelvic fins are on the same line of origin. [5] [6] All members of the subfamily have a small dorsal adipose fin. [7] Piabucus typically have longer pectoral fins and a deeper chest than Iguanodectes (sometimes described as a more pronounced "pectoral keel"). [8] The lateral line is complete in all species. [7] The species Iguanodectes geisleri has some morphological differences when compared to its congeners; its dorsal fin originates in the middle of the body, as opposed to behind the middle, and its anal fin is shorter in length. [8]

The mouth is small, terminal, and does not extend past or under the eye. [7] The maxilla is equipped with multicuspid incisor teeth, contracted at the base and flaring outwards. [5] The premaxilla has one or two teeth on each side in all species, except for Piabucus melanostomus, which lacks this "outer set". [7] This dentition is primarily used for an herbivorous diet, at least in Iguanodectes, but little is known of the subfamily's ecology outside of this. [8]

Taxonomy

An 1800s-era illustration of Piabuca argentina, now named Piabucus dentatus. Piabuca argentina - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - UBA01 IZ14700063.tif
An 1800s-era illustration of Piabuca argentina, now named Piabucus dentatus.

When first classified in 1909 by ichthyologist Carl H. Eigenmann, Iguanodectinae was placed in the family Characidae; at the time, it had a sole representative in the genus Iguanodectes . [9] By 1929, this definition had expanded to include Piabucus. [3] In 1954, James Erwin Böhlke confirmed by way of morphology that Iguanodectes and Piabucus should both be in Iguanodectinae. [10] The monophyly of the subfamily was noted by Richard P. Vari in research from the year 1977. [5] Research by Oliviera et al., based both in phylogeny and morphology, prompted a move to the family Iguanodectidae from Characidae in 2011; this move was also done to keep Characidae monophyletic. [11] The same research also moved the monogeneric Bryconops clade into Iguanodectidae, leaving Iguanodectinae and Bryconops as the only two taxa therein. [12]

While Iguanodectinae is recognized by sources like OBIS and the World Register of Marine Species, [13] [12] other sources such as NCBI and the Interim Register of Marine and Nonmarine Genera consider it synonymous with Iguanodectidae. [14] [15] Eschmeyer's Catalog of Fishes and GBIF simply don't acknowledge it, uniting the genera therein. [16] [17] ITIS still considers it synonymous with Characidae. [18]

Iguanodectes is the more speciose of the two genera, with 8 members. [2] Piabucus has 3. [1]

Iguanodectes (Cope, 1982)

Piabucus (Oken, 1817)

Habitat

All members of Iguanodectinae from both genera reside in South America. [17] [19] They can be found in the Amazon, Orinoco, Tocantins, and Paraguay rivers, as well as all major tributaries of the Amazon. [8] Of these, the Paraguay is the least-populated; Iguanodectinae is only represented therein by a few species in the genus Piabucus. [20] When in captivity, species from both genera have been observed to be intolerant of poor water conditions, demonstrating a preference for a well-oxygenated environment. [21] [22] They seem to prefer swimming near the surface of the water.

Etymology

The subfamily Iguanodectinae gets its name from the genus Iguanodectes, which used to be its sole representative. [9] Carl H. Eigenmann noted in 1929 that the root allusion was not made clear in the original materials for Iguanodectes; [3] modern consensus, however, agrees with the analysis he subsequently provided, that it originates in "iguana", the lizard, and the Greek word "dectes", which means "to bite" or "to devour". [23] Drawing from this, the common name "lizard bite tetra" for the entire family Iguanodectidae has been proposed, but has not been accepted. [24] [25] The subfamily Iguanodectinae also has no accepted common name. [26]

In aquaria

An unidentified Iguanodectes sp. Iguanodectes sp.jpg
An unidentified Iguanodectes sp.

Though not as popular as many other species of tetra, several members of Iguanodectinae are seen in the aquarium trade. Piabucus dentatus, sometimes called the Piabuco tetra, is taken from the wild for such purposes, but is not at risk of going extinct from it. [22] [27] Reports from hobbyists as recently as "the summer of 2018" show that such collection is still ongoing. [28] It tends to form groups, so aquarists are recommended to house as many as at least 6 at a time. [22] [29] This goes for the other species of Piabucus as well; all three are sometimes grouped as Piabucus sp. and called "chin tetras". [30] This is likely due to distinct markings on the lower jaw. [22]

Fish from Iguanodectes are slightly more common than from Piabucus, but are still infrequent in the trade. I. geisleri is sold under the name "red line lizard tetra", and I. spilurus has the name "green line lizard tetra". [21] [31] I. adujai looks quite similar to I. geisleri, so is sometimes part of the same stock. [32]

Related Research Articles

<span class="mw-page-title-main">Characidae</span> Family of fishes

Characidae, the characids or characins, is a family of freshwater subtropical and tropical fish belonging to the order Characiformes. The name "characins" is an historical one, but scientists today tend to prefer "characids" to reflect their status as a, by and large, monophyletic group. To arrive there, this family has undergone much systematic and taxonomic change. Among those fishes remaining in the Characidae currently are the tetras, comprising the very similar genera Hemigrammus and Hyphessobrycon, as well as a few related forms, such as the cave and neon tetras. Fish of this family are important as food in several regions, and also constitute a large percentage of captive freshwater aquarium fish species.

<i>Iguanodectes</i> Genus of fishes

Iguanodectes is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry. Alongside the genus Piabucus, it is in the subfamily Iguanodectinae, which in turn is in the family Iguanodectidae. The genus Bryconops, which is also in Iguanodectidae, makes up a sister clade to Iguanodectinae.

<i>Piabucus</i> Genus of fishes

Piabucus is a genus of freshwater tetras in the family Iguanodectidae. All three species are found in South America, largely the Amazon and its major tributaries. None of them are longer than half a foot long, with the largest reaching a maximum size of 12.9 cm (5.1 in), and they are slender, with relatively deep chests and long pectoral fins. Their scales are pale or silvery, with lateral lines that stand out.

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

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

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

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

<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.

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

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

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

Bryconops vibex is a small freshwater fish from the rivers of Venezuela, known solely from the Rio Cataniapo. The body is slender, though with an element of sturdiness, and it has one humeral spot by each pectoral fin. It bears visual similarities to several congeners, but can be differentiated by way of many factors.

Bryconops hexalepis is a small iguanodectid fish from the rivers of Brazil. It is solely found in the drainage of the Rio Tocantins. Rather elongate and quite slender, it is considered one of the smaller species of its genus, with tall scales and large eyes.

Iguanodectes adujai is a species of freshwater fish that inhabits the rivers of South America. It largely prefers slow-moving blackwater habitats, though it has a slender body that suggests a further affinity for flowing water. It has a distinct lateral stripe in two horizontal sections, with bright-red at the top and yellow at the bottom.

<i>Iguanodectes geisleri</i> Species of fish

Iguanodectes geisleri, the red-line lizard tetra, is a species of freshwater fish from South America. It is a small species, largely herbivorous with some omnivorous traits, that prefers to live in schools and is partial to shallow waters, especially in blackwater habitats. Some aspects of its body plan are unique amongst its genus, including the position and length of the anal fin.

Iguanodectes gracilis is a small species of freshwater fish from South America. It is known solely from the Rio Negro river system, which restricts its range only to Brazil. The name "gracilis" is in reference to a slender body shape, alongside the diminutive nature of I. gracilis - it is the smallest member of the genus Iguanodectes.

Iguanodectes polylepis is a species of freshwater fish from the rivers of South America. Its range is restricted to Brazil, where it inhabits the Madeira and Purus river basins. It is one of the larger members of the genus, but remains generally small, only a little over a quarter-foot long.

Iguanodectes purusii is a small freshwater fish from the rivers of South America. It is largely herbivorous, and prefers to live in schools. The name "purusii" originates from the species' type locality, the Purus river basin of Brazil, with a range that also extends into Peru. Furthermore, it has been documented from the Amazon, Madeira, Guaporé, and Pastaza rivers, but specific study of its ecology is otherwise lacking.

Iguanodectes spilurus, the green-line lizard tetra, is a small characiform fish from the rivers of South America. It is not a well-studied species, but research is available, including data from hobbyists that keep it as an ornamental fish. It has a distinct lateral stripe of reflective-green scales, and lacks any red markings therein; red is common in congeners' lateral stripes.

Iguanodectes variatus is a small freshwater fish, described from the rivers of South America in 1993. It has a minor presence in the aquarium trade, but lacks the popularity that would make excessive wild capture a legitimate threat. That being said, the threats facing South American aquatic environments are of ongoing concern for the associated biodiversity. Still, I. variatus has been recorded from various rivers and has shown general adaptability to its environment, which speaks to a high survivability.

Piabucus caudomaculatus is a small freshwater fish inhabiting the rivers of South America. It was the first member of the family Iguanodectidae to be reported from Bolivia, and it remains endemic to the region, found solely in the Mamoré river basin. It displays a preference for slow-moving waterways and has a largely insectivorous diet.

Piabucus dentatus, also called the chin tetra or the coastal piabucus, is a small freshwater fish from the rivers of South America. It has a wide range that includes multiple coastal drainage systems, and was once mistakenly cited from Peru. Preferred habitats are generally high in silt content and are slow-moving, including floodplain streams and estuaries.

<i>Piabucus melanostoma</i> Species of fish

Piabucus melanostoma, sometimes called the chin tetra, is a small species of freshwater fish from the rivers of South America. It is the second-largest species of the genus, but still only reaches about 12 cm long. Occasionally found in captivity, it has an appealing iridescent-silver coloration. It is amongst the largest of fish still considered "tetras" in the aquarium hobby.

References

  1. 1 2 Froese, Rainer and Pauly, Daniel, eds. (2022). Species of Piabucus in FishBase . February 2022 version.
  2. 1 2 Froese, Rainer and Pauly, Daniel, eds. (2022). Species of Iguanodectes in FishBase . February 2022 version.
  3. 1 2 3 Eigenmann, Carl H.; Meyers, George S. (1917–1929). The American Characidae. Cambridge. pp. 493–499. Retrieved 3 February 2022.
  4. ↑ Lourenço da Silva, E.; Piscor, D.; Ponzeto, J. M.; Centofante, L.; Alves, A. L.; Parise-Maltempi, P. P. (2012). "Cytogenetic characterisation of the ornamental freshwater fish, Piabucus melanostomus (Iguanodectinae) from Brazilian wetlands and its relation with species of Characidae basal group". Reviews in Fish Biology and Fisheries. 22 (2): 477–484. doi:10.1007/s11160-011-9238-2. ISSN   0960-3166. S2CID   17712507.
  5. 1 2 3 Vari, Richard P. (26 January 1977). "Notes on the characoid subfamily Iguanodectinae, with a description of a new species". American Museum Novitates (2612). hdl:2246/2012 – via AMNH Digital Repository.
  6. ↑ Mirande, Juan Marcos (2010). "Phylogeny of the family Characidae (Teleostei: Characiformes): from characters to taxonomy". Neotropical Ichthyology. 8 (3): 385–568. doi: 10.1590/S1679-62252010000300001 . hdl: 11336/77449 . ISSN   1679-6225.
  7. 1 2 3 4 Böhlke, James E. (1954-02-01). "XV.—Studies on fishes of the family Characidae.—No. 6. A synopsis of the Iguanodectinae". Annals and Magazine of Natural History. 7 (74): 97–104. doi:10.1080/00222935408651699. ISSN   0374-5481.
  8. 1 2 3 4 Check list of the freshwater fishes of South and Central America. Roberto E. Reis, Sven O. Kullander, Carl J. Ferraris, Pontifícia Universidade Católica do Rio Grande do Sul. Museu de Ciências e Tecnologia. Porto Alegre, Brasil: EDIPUCRS. 2003. ISBN   85-7430-361-5. OCLC   54496178.{{cite book}}: CS1 maint: others (link)
  9. 1 2 Eigenmann, Carl H. (1910). Catalogue and bibliography of the fresh water fishes of the Americas south of the Tropic of Cancer. Lancaster, Pa.: Press of the New Era Printing Co. doi:10.5962/bhl.title.11953.
  10. ↑ Böhlke, J. (1954-02-01). "XV.—Studies on fishes of the family Characidae.—No. 6. A synopsis of the Iguanodectinae". Annals and Magazine of Natural History. 7 (74): 97–104. doi:10.1080/00222935408651699. ISSN   0374-5481.
  11. ↑ Oliveira, C., Avelino, G.S., Abe, K.T., Mariguela, T.C., Benine, R.C., Orti, G., Vari, R.P., & Correa e Castro, R.M. (2011): Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling. BMC Evolutionary Biology, 11: 275. doi: 10.1186/1471-2148-11-275
  12. 1 2 "WoRMS - World Register of Marine Species - Iguanodectidae Eigenmann, 1909". www.marinespecies.org. Retrieved 2022-02-03.
  13. ↑ "Iguanodectidae Eigenmann, 1909 - Ocean Biodiversity Information System". portal.obis.org. Retrieved 2022-02-03.
  14. ↑ "IRMNG - Iguanodectidae". Interim Register of Marine and Nonmarine Genera. Retrieved 2022-02-03.
  15. ↑ "Taxonomy browser (Iguanodectidae)". NCBI. Retrieved 2022-02-03.
  16. ↑ "Eschmeyer's Catalog of Fishes Classification". California Academy of Sciences. Retrieved 2022-02-03.
  17. 1 2 "Iguanodectidae". GBIF. Retrieved 2022-02-03.
  18. ↑ "ITIS - Report: Iguanodectinae". www.itis.gov. Retrieved 2022-02-03.
  19. ↑ "COPEPEDIA summary for Iguanodectinae : T5015394 : Subfamily". www.st.nmfs.noaa.gov. Retrieved 2022-02-06.
  20. ↑ Borba, Rafael Splendore de; Silva, Edson Lourenço da; Ponzetto, Josi Margarete; Pozzobon, Allan Pierre Bonetti; Centofante, Liano; Alves, Anderson Luis; Parise-Maltempi, Patrícia Pasquali (March 2013). "Genetic structure of the ornamental tetra fish species Piabucus melanostomus Holmberg, 1891 (CHARACIDAE, IGUANODECTINAE) in the Brazilian Pantanal wetlands inferred by mitochondrial DNA sequences". Biota Neotropica. 13: 42–46. doi: 10.1590/S1676-06032013000100004 . hdl: 11449/19632 . ISSN   1676-0611.
  21. 1 2 "Iguanodectes spilurus (Green Line Lizard Tetra)". Seriously Fish. Retrieved 3 February 2022.
  22. 1 2 3 4 "Piabucus dentatus (Piabuco Tetra) — Seriously Fish". Seriously Fish. Retrieved 2022-02-08.
  23. ↑ Scharpf, Christopher; Lazara, Kenneth J. (15 September 2020). "Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE". The ETYFish Project. Retrieved 2 February 2022.
  24. ↑ Froese, Rainer, and Daniel Pauly, eds. (2022). "Iguanodectidae" in FishBase . February 2022 version.
  25. ↑ "Iguanodectidae names - Encyclopedia of Life". eol.org. Retrieved 2022-02-03.
  26. ↑ "Iguanodectinae Eigenmann 1909 names - Encyclopedia of Life". eol.org. Retrieved 2022-02-08.
  27. ↑ Taphorn, D.C., DoNascimiento, C., Herrera-Collazos, E.E., Rodríguez-Olarte, D., Usma, S. & Villa-Navarro, F. 2021. Piabucus dentatus. The IUCN Red List of Threatened Species 2021: e.T49830090A176108340. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T49830090A176108340.en. Accessed on 08 February 2022.
  28. ↑ Fischer, Eckhard (3 January 2020). "Piabucus dentatus - A Rare, Unusual Tetra". Hildesheim Terrarium and Aquarium Club. Retrieved 8 February 2022.
  29. ↑ "Piabuco tetra (Piabucus dentatus)". Aqua-Fish Database. Retrieved 2022-02-08.
  30. ↑ "Chin tetra, Piabucus sp. - Practical Fishkeeping". www.practicalfishkeeping.co.uk. June 2007. Retrieved 2022-02-08.
  31. ↑ "Red Line Lizard Tetra (Iguanodectes geisleri)". Aqua-Imports. Retrieved 3 February 2022.
  32. ↑ "Iguanodectes adujai — Seriously Fish". Seriously Fish. Retrieved 2022-02-08.
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