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.

Iguanodectes adujai
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Iguanodectidae
Genus: Iguanodectes
Species:
I. adujai
Binomial name
Iguanodectes adujai
Géry, 1970

Though rare, it is seen in the aquarium trade, and is sometimes captured from the wild for collection or sale. I. adujai is sometimes sold in the same stock as congener I. geisleri, due to a markedly similar appearance.

Description

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Iguanodectes adujai is a small tetra with a slender build, reaching a maximum of 6.2 cm (2.4 in) standard length (SL).[1] The general body shape has been described as similar to a smelt or minnow, something the genus Iguanodectes shares with sister genus Piabucus.[2][3][4] I. adujai specifically has pale-silver scales, a yellowish underside, and a red lateral stripe that ends in a blotch of pigmentation at the caudal fin.[5]

The lateral stripe can be used to tell two similar-looking species, Iguanodectes adujai and Iguanodectes geisleri, apart. In geisleri, the lateral stripe is three colors (red, yellow, and black, top-to-bottom), whereas in adujai it is only two (red and yellow).[6] Other identifying characteristics of I. adujai include the anal-fin origin lining up with the dorsal-fin origin (versus being located posterior to the dorsal-fin origin in I. geisleri) and 28-34 anal-fin rays (versus 20-25).[7]

Taxonomy

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There are a total of 8 accepted species in the genus Iguanodectes.[8] I. adujai is a fairly recent addition in comparison with other members, the earliest of which (Iguanodectes spilurus) was named in 1864, though considered a member of related genus Piabucus at the time. The latest additions were all named in 1993.[9] I. adujai has no known scientific synonyms, having retained its original name since discovery.[10]

In terms of a common name, I. adujai is sometimes sold under the name "rust-stripe tetra" or "red line lizard tetra".[11] It should not be confused with congener I. geisleri, which is somewhat more common and is sold under the same name.[6] I. adujai has also been sold as the "rainbow lizard tetra" or the "slender tetra".[12][13] The variety in nomenclature indicates weak consensus on how to refer to the species.

Most members of Iguanodectes are referred to as "piaba" in colloquial Brazilian settings.[4][14]

Etymology

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The specific name "adujai" originates from the igarapé Adujá, which is the type locality of I. adujai. "Iguanodectes" comes from "iguana", the lizard, and "dectes", meaning "bite" or "tooth"; though it was not made clear in the original text, it is assumed that this is in reference to the "lizard-like" dentition.[15]

Distribution and habitat

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Iguanodectes adujai is known from Brazil, Venezuela, and Colombia.[16] Its type locality speaks to a preference for blackwater habitats, which are characterized by plentiful riparian vegetation and a substrate largely composed of leaf litter.[7] Specifically, it was first located in the igarapé Aduja,[15] which is a tributary of the Rio Itu, located in the middle Rio Negro basin.[17]

The Rio Negro basin is well-known for its floodplains, including an area in which the Itu is located,[18] and associated flooding cycles may have an influence on I. adujai's diet and behavior. The stretch of wetlands therein is inundated with blackwater rivers.[19] Within the Itu specifically, iron deposits are not uncommon.[20] The relevant riparian vegetation largely consists of sedges and palm trees.[21]

Diet and ecology

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Iguanodectes adujai is an omnivorous species, though many Iguanodectes are largely herbivores.[4] It seems to be a fairly opportunistic feeder, including crustaceans, insects, algae, fallen fruit, and leaf litter in its diet.[22] Living in a floodplain means that its food sources fluctuate with the seasons. Little else is known of its interaction with its environment and the food web in its native range.

Conservation status

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Iguanodectes adujai has not been evaluated by the IUCN, and is thus lacking in species-specific population evaluation.[23] Nonetheless, freshwater aquatic habitats - especially wetlands - in South America are frequently under pressure from various ongoing anthropogenic hazards, including illegal mining and infrastructure development.[24]

The wetlands of South America are known for their biodiversity, but also for their fragility. As such, conservation efforts are often undertaken to protect them, which offers wetland-dwelling species like I. adujai continued stability.[19][25] Still, there are some legal and social complications surrounding protected sites therein, which may interfere with their role as sanctuaries for endemic species.[24]

Presence and behavior in aquaria

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Iguanodectes adujai is exported from its native habitat to various locations, including Germany and Poland, on an uncommon basis.[22][26] Aquarists describe a largely calm disposition, though males may get combative amongst themselves to establish a hierarchy.[5] It is reportedly sensitive to poor water conditions.[22]

Iguanodectes adujai and Iguanodectes geisleri are sometimes sold in the same stock and labeled as the same species because they may be difficult for the layperson to tell apart.[7]

References

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  1. ^ 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)
  2. ^ Eigenmann, Carl H.; Meyers, George S. (1917–1929). The American Characidae. Cambridge. pp. 493–499. Retrieved 29 November 2022.
  3. ^ 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.
  4. ^ a b c "THE FISH FAMILIES". Field Guide to the Fishes of the Amazon, Orinoco, and Guianas, edited by Peter van der Sleen and James S. Albert, Princeton: Princeton University Press, 2017, pp. 95-96. https://doi.org/10.1515/9781400888801-009
  5. ^ a b "Long Bodies, Long Ranges". Wet Spot Tropical Fish. 3 September 2021. Retrieved 29 November 2022.
  6. ^ a b "Iguanodectes geisleri (Red Line Lizard Tetra)". Seriously Fish. Retrieved 28 November 2022.
  7. ^ a b c "Iguanodectes adujai — Seriously Fish". Seriously Fish. Retrieved 28 November 2022.
  8. ^ Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Iguanodectes". FishBase. November 2022 version.
  9. ^ "WoRMS - World Register of Marine Species - Iguanodectes Cope, 1872". World Register of Marine Species. Retrieved 29 November 2022.
  10. ^ "Iguanodectes adujai Géry, 1970". gbif.org. Global Biodiversity Information System. Retrieved 29 November 2022.
  11. ^ "Iguanodectes adujai - Roststreifen-Eidechsensalmler (WF)". unter-wasser-freiburg.de (in German). UNTER WASSER. Retrieved 29 November 2022.
  12. ^ James, EA (15 March 2021). "Forum - Rainbow Lizard Tetra (Iguanodectes Adujai)". ukaps.org. UK Aquatic Plant Society. Retrieved 29 November 2022.
  13. ^ "Livestock - Iguanodectes adujai". wetspottropicalfish.com. Wet Spot Tropical Fish. Retrieved 29 November 2022.
  14. ^ "Instrução Normativa Interministerial" (PDF). Diário Oficial da União (Federal Official Gazette) (in Portuguese). No. 3. Ministério da Pesca e Aquacultura. 3 January 2012. pp. 26–42. Retrieved 29 November 2022.
  15. ^ a b Scharpf, Christopher; Lazara, Kenneth J. (15 September 2020). "Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE". The ETYFish Project. Archived from the original on 6 November 2019. Retrieved 28 November 2022.
  16. ^ van der Laan, Richard; Fricke, Ron. "adujai, Iguanodectes". Eschmeyer's Catalog of Fishes. California Academy of Sciences. Retrieved 29 November 2022.
  17. ^ Rocha, Marcelo Salles; Oliveira, Renildo Ribeiro de; Py-Daniel, Lúcia H. Rapp (2008). "Scoloplax baskini: a new spiny dwarf catfish from rio Aripuanã, Amazonas, Brazil (Loricarioidei: Scoloplacidae)". Neotropical Ichthyology. 6 (3): 323–328. doi:10.1590/S1679-62252008000300005. S2CID 84735813. Retrieved 29 November 2022.
  18. ^ Belger, L.; Forsberg, B.R.; Melack, J.M. (2014). "LBA-ECO LC-07 CO2 and CH4 Flux from Wetlands, Negro River Basin, Brazil: 2004-2006". Ornl Daac: 0.473257 MB. doi:10.3334/ORNLDAAC/1209. Retrieved 29 November 2022.
  19. ^ a b Sánchez, Carolina Obregón (12 February 2021). "Challenges in the management of Brazilian wetlands: Negro and Juruá Rivers". Aguas Amazonicas. Wildlife Conservation Society. Retrieved 29 November 2022.
  20. ^ Trentin, Romario; Santos, Leonardo José Cordeiro; Robaina, Luís Eduardo de Souza (April 2012). "Compartimentação geomorfológica da bacia hidrográfica do Rio Itu: oeste do Rio Grande do Sul - Brasil". Sociedade & Natureza. 24: 127–142. doi:10.1590/S1982-45132012000100011. Retrieved 29 November 2022.
  21. ^ Melack, John M.; Basso, Luana S.; Fleischmann, Ayan S.; Botía, Santiago; Guo, Mingyang; Zhou, Wencai; Barbosa, Pedro M.; Amaral, Joao H.F.; MacIntyre, Sally (2022). "Challenges Regionalizing Methane Emissions Using Aquatic Environments in the Amazon Basin as Examples". Frontiers in Environmental Science. 10. doi:10.3389/fenvs.2022.866082.
  22. ^ a b c "Iguanodectes adujai". akwa-mania.mud.pl. AKWA-MANIA. Retrieved 29 November 2022.
  23. ^ Froese, Rainer; Pauly, Daniel (eds.). "Iguanodectes adujai". FishBase. November 2022 version.
  24. ^ a b Ribeiro, Soraya; Moura, Rafael G.; Stenert, Cristina; Florín, Maximo; Maltchik, Leonardo (1 December 2020). "Land use in Brazilian continental wetland Ramsar sites". Land Use Policy. 99: 104851. doi:10.1016/j.landusepol.2020.104851. hdl:10578/29585. S2CID 225018502. Retrieved 29 November 2022.
  25. ^ "Protection for Brazilian wetlands". phys.org. 14 September 2015. Retrieved 29 November 2022.
  26. ^ Schäfer, Frank (April 2014). "Iguanodectes arrived". aquariumglaser.de. Aquarium Glaser GmbH. Retrieved 29 November 2022.