Iguanodectes

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Iguanodectes
Iguanodectes sp.jpg
Iguanodectes sp.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Iguanodectes
Cope, 1872

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.

Contents

Description

Members of Iguanodectes are relatively slender, shaped somewhat like minnows; ichthyologists Carl H. Eigenmann and James Erwin Böhlke both compared them to smelt in general body composition. [1] [2] The largest (Iguanodectes variatus) reaches 10.3 cm (4.1 in) at a maximum in SL, and the smallest (Iguanodectes gracilis) 4.6 cm (1.6 in). [3] This size makes them relatively easy to keep in captivity, and so several species of Iguanodectes - as with the whole subfamily Iguanodectinae - are seen in aquariums from time to time, with the potential to be a bigger target. [4] However, they are not as common as many other species of tetra. I. geisleri is sold under the name "red line lizard tetra", and I. spilurus has the name "green line lizard tetra". [5] [6] Because I. adujai looks quite similar to I. geisleri, the two species are sometimes found in the same stock. [7]

In all species of Iguanodectes, the lateral line is complete. [2] Sometimes, the scales of the lateral line disrupt coloration that is otherwise fairly uniform, and is often silvery. For instance, I. geisleri has a red stripe on the dorsal side of a dark lateral line, and I. spilurus has lateral line scales that reflect green in certain lighting. Because of this, these two species are sometimes called the red line lizard tetra and green line lizard tetra, respectively. [5] [6] [8] Many species of Iguanodectes lack a common name.

Iguanodectes geisleri Iguanodectes geisleri - AquaPorteDoree.JPG
Iguanodectes geisleri

The dorsal fin is usually located behind the middle of the body and behind the start of the pelvic fin, though they sometimes share a line of origin. [9] This is somewhat different in I. geisleri, whose dorsal fin is located closer to the center; I. geisleri also has shorter pelvic fins than its congeners. [10] All species have a small adipose fin. [2] When Iguanodectes is compared to the genus Piabucus, the other member of the subfamily Iguanodectinae, the pectoral fins are shorter and the chest is not as deep. [10]

The mouth is terminal and small, stopping before it reaches under the eye. [2] In all Iguanodectes, the maxilla bears a set of multicuspid incisor teeth that are flared out at the tip and contracted at the base. [9] The premaxilla also has one or two teeth on each side, forming an "outer set". [2] Little else is known of their ecology, but members of Iguanodectes utilize this setup for a primarily herbivorous diet. [10] Though the allusion was not clear in the original text, [1] modern etymologists has come to the conclusion that the name of the genus originates in Greek and translates to "lizard bite", in reference to the dentition. [11] As a result of this, the common name "lizard bite tetra" has been suggested for the entire family Iguanodectidae, but has not been accepted. [12] [13]

Taxonomy

There are 8 valid species in Iguanodectes. [3] In alphabetical order, they are:

Iguanodectes, along with the genus Piabucus , is in the subfamily Iguanodectinae; In turn, Iguanodectinae is in the family Iguanodectidae, both of which get their name from Iguanodectes. [11] In 1909, ichthyologist Carl H. Eigenmann proposed Iguanodectinae as a subfamily, which was solely home to Iguanodectes at the time. [14] In 1929, Iguanodectinae grew to encompass Piabucus as well. [1] In 1954, ichthyologist James Erwin Böhlke reconfirmed that the two genera should form a clade by way of morphology. [2] Iguanodectinae and the monotypic Bryconops clade make up the family Iguanodectidae. [15] [16]

The first member of Iguanodectes to be classified, I. spilurus, was originally described as Piabuca spilurus by zoologist Albert Günther in 1864. [17] [18] In 1872, biologist Edward Drinker Cope described the same species as Iguanodectes tenuis. [19] [20] Cope's placement of the species into a new genus was later accepted, but it adopted the specific epithet given by Günther. [2]

Upon being described, Iguanodectes was considered a characin (member of the family Characidae). This was still the case when it was placed in the subfamily Iguanodectinae in 1909. [14] However, research by Oliviera et al. in 2011 prompted authorities to move Iguanodectinae and Bryconops to Iguanodectidae, which had been revived from Eigenmann's work. [21] This was done based on morphological and phylogenetic evidence, as well as keeping Characidae monophyletic. [22] As a fairly new taxon, Iguanodectinae is not listed in several databases; sources such as NCBI and the Interim Register of Marine and Nonmarine Genera consider it synonymous with Iguanodectidae, [23] [24] where Eschmeyer's Catalog of Fishes and GBIF simply don't acknowledge it, uniting all three genera in Iguanodectidae. [25] [26] However, sources such as OBIS and the World Register of Marine Species consider it valid. [27] [28]

Habitat

Like all members of the family Iguanodectidae, members of Iguanodectes solely inhabit freshwater environments in South America. [29] Iguanodectes specifically can be found in the Amazon river and all of its major tributaries, as well as the Guaporé, Trombetas, Orinoco, and Tocantins rivers. [10] [30] Though their ecology has not been studied extensively, captive specimens demonstrate a poor tolerance for adverse water conditions. [6] They also prefer flowing water, and have a proclivity for swimming near the surface. Some species, like I. geisleri, are known to live in blackwater environments. [8]

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>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.

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

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. There is minor, but ongoing, debate regarding its taxonomy.

<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 colanegra is a small, slender-bodied species of freshwater fish from South America, about 3.5 in long. It has a black tail fin that bears hints of red, and its scales are dark along the back, transitioning to a silver belly. It is endemic to a single river system in Venezuela, the Rio Caroní.

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

Bryconops colaroja is a small species of fish endemic to tributaries and creeks of the Cuyuni River basin in Venezuela. The specific epithet "colaroja" means "red tailed", and it gets this name from its most distinctive feature - a deep red caudal fin, largely unique amongst members of its genus.

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.

Bryconops inpai is a small freshwater fish native to the rivers of South America. It only lives in two particular river systems - the Casiquiare and Negro - which means that its range is restricted to the northern half of the continent. It has indistinct humeral spots, and is bluish-silver in life, which is unusual for members of Bryconops; they are more often plain silver or greenish-silver.

<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.

References

  1. 1 2 3 Eigenmann, Carl H.; Meyers, George S. (1917–1929). The American Characidae. Cambridge. pp. 493–499. Retrieved 16 February 2022.
  2. 1 2 3 4 5 6 7 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.
  3. 1 2 Froese, Rainer and Pauly, Daniel, eds. (2022). Species of Iguanodectes in FishBase . February 2022 version.
  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 "Red Line Lizard Tetra (Iguanodectes geisleri)". Aqua-Imports. Retrieved 16 February 2022.
  6. 1 2 3 "Iguanodectes spilurus (Green Line Lizard Tetra)". Seriously Fish. Retrieved 16 February 2022.
  7. ↑ "Iguanodectes adujai — Seriously Fish". Seriously Fish. Retrieved 2022-02-16.
  8. 1 2 "Iguanodectes geisleri (Red Line Lizard Tetra)". Seriously Fish. Retrieved 16 February 2022.
  9. 1 2 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.
  10. 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)
  11. 1 2 Scharpf, Christopher; Lazara, Kenneth J. (15 September 2020). "Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE". The ETYFish Project. Retrieved 16 February 2022.
  12. ↑ Froese, Rainer, and Daniel Pauly, eds. (2022). "Iguanodectidae" in FishBase . February 2022 version.
  13. ↑ "Iguanodectidae names - Encyclopedia of Life". Encyclopedia of Life. Retrieved 2022-02-16.
  14. 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.
  15. ↑ "COPEPEDIA summary for Iguanodectidae : T5006063 : Family". NOAA Copepedia. Retrieved 2022-02-16.
  16. ↑ "WoRMS - World Register of Marine Species - Iguanodectidae Eigenmann, 1909". World Register of Marine Species. Retrieved 2022-02-16.
  17. ↑ Günther, Albert C. L. G. (1864). Catalogue of the fishes in the British Museum. Vol. 5. London: British Museum (Natural History), Department of Zoology. p. 344. doi:10.5962/bhl.title.8809. OCLC   232550669.
  18. ↑ "Iguanodectes spilurus (Günther, 1864)". Global Biodiversity Information Facility. Retrieved 2022-02-16.
  19. ↑ Cope, E. D. (1872). On the fishes of the Ambyiacu River. Philadelphia: Academy of Natural Sciences. p. 260. doi:10.5962/bhl.title.11798.
  20. ↑ "WoRMS - World Register of Marine Species - Iguanodectes Cope, 1872". www.marinespecies.org. Retrieved 2022-02-16.
  21. ↑ Froese, Rainer, and Daniel Pauly, eds. (2022). "Iguanodectidae" in FishBase . February 2022 version.
  22. ↑ 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
  23. ↑ "Taxonomy browser (Iguanodectidae)". NCBI. Retrieved 2022-02-03.
  24. ↑ "IRMNG - Iguanodectidae". Interim Register of Marine and Nonmarine Genera. Retrieved 2022-02-03.
  25. ↑ "Eschmeyer's Catalog of Fishes Classification". California Academy of Sciences. Retrieved 2022-02-16.
  26. ↑ "Iguanodectidae". Global Biodiversity Information Facility. Retrieved 2022-02-16.
  27. ↑ "Iguanodectidae Eigenmann, 1909 - Ocean Biodiversity Information System". Ocean Biodiversity Information System. Retrieved 2022-02-03.
  28. ↑ "WoRMS - World Register of Marine Species - Iguanodectidae Eigenmann, 1909". World Register of Marine Species. Retrieved 2022-02-03.
  29. ↑ "COPEPEDIA summary for Iguanodectes : T5015580 : Genus". NOAA Copepedia. Retrieved 2022-02-16.
  30. ↑ "Iguanodectes variatus — Seriously Fish". Seriously Fish. Retrieved 2022-02-16.
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