Hypopygus
| Hypopygus | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Gymnotiformes |
| Family: | Rhamphichthyidae |
| Genus: | Hypopygus Hoedeman, 1962[1] |
| Type species | |
| Hypopygus lepturus Hoedeman, 1962[1]
| |
| Synonyms[1] | |
|
Stegostenopos Triques, 1997 | |
Hypopygus is a genus of South American gymnotiform knifefishes native to the Amazon, Orinoco and upper Paraguay basins, as well as rivers in the Guianas.[2][3] They are often common, and found near submerged roots, aquatic vegetation and leaf-litter in streams, edges of rivers and floodplains.[2] They are regularly found among vegetation in floating meadows, a habitat that often contains little oxygen, but they are well-adapted to this.[4]
They are well-camouflaged and brown in color with a banded/mottled pattern.[2][3][5] They generally resemble the related Steatogenys, but are smaller,[6] reaching up to 5.9–12.2 cm (2.3–4.8 in) in total length depending on the exact species of Hypopygus.[7] The smallest is H. hoedemani, which is the second-smallest knifefish,[2] after Microsternarchus brevis.[8] They are nocturnal and feed on small invertebrates. During the day they remain hidden, often in groups that may number several dozen individuals.[2]
Taxonomy and species
[edit]Hypopygus has traditionally been included in the family Hypopomidae,[9] but a comprehensive molecular study from 2015 showed it belongs in Rhamphichthyidae,[10] and this has been followed by recent authorities.[11][12]
Hypopygus contains the following species:[13]
- Hypopygus benoneae L. A. W. Peixoto, Dutra, de Santana & Wosiacki, 2013
- Hypopygus cryptogenes (Triques, 1997)
- Hypopygus hoedemani de Santana & Crampton, 2011 (Hoedeman's Hypopygus)
- Hypopygus isbruckeri de Santana & Crampton, 2011 (Isbrücker's Hypopygus)
- Hypopygus lepturus Hoedeman, 1962
- Hypopygus minissimus de Santana & Crampton, 2011
- Hypopygus neblinae Mago-Leccia, 1994
- Hypopygus nijsseni de Santana & Crampton, 2011 (Nijssen's Hypopygus)
- Hypopygus ortegai de Santana & Crampton, 2011 (Ortega's Hypopygus)
- Hypopygus varii Campos-da-Paz 2018
References
[edit]- ^ a b c Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Rhamphichthyinae". Catalog of Fishes. California Academy of Sciences. Retrieved 3 June 2025.
- ^ a b c d e de Santana, C.D. & W.G.R. Crampton (2011). "Phylogenetic interrelationships, taxonomy, and reductive evolution in the Neotropical electric fish genus Hypopygus (Teleostei, Ostariophysi, Gymnotiformes)". Zoological Journal of the Linnean Society. 163 (4): 1096–1156. doi:10.1111/j.1096-3642.2011.00736.x.
- ^ a b Peixoto, Luiz Antônio Wanderley; Dutra, Guilherme Moreira; de Santana, Carlos David & Wosiacki, Wolmar Benjamin (2013). "A new species of the electric fish genus Hypopygus (Gymnotiformes: Hypopomidae) from the Lower Amazon Basin, Brazil". Copeia. 2013 (2): 232–237. doi:10.1643/CI-12-087. S2CID 84089305.
- ^ Carvalho, L.N.; L. Fidelis; R. Arruda; A. Galuch & K. Zuanon (2013). "Second floor, please: the fish fauna of floating litter banks in Amazonian streams and rivers". Neotropical Ichthyology. 11 (1): 78–91. doi:10.1590/S1679-62252013000100010.
- ^ Nijssen, H. & I.J.H. Isbrücker (1972). "On Hypopygus lepturus, a little known dwarf gymnotid fish from South America (Pisces, Cypriniformes, Gymnotoidei)". Zoologische Mededelingen. 14763: 160–176.
- ^ Crampton, W.G.R.; D.C. Thorsen; J.S. Albert & N.R. Lovejoy (2004). "Steatogenys ocellatus: a new species of neotropical electric fish (Gymnotiformes: Hypopomidae) from the Lowland Amazon Basin". Copeia. 2004 (1): 78–91. doi:10.1643/ci-03-072ri. S2CID 85693926.
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Hypopygus". FishBase. April 2018 version.
- ^ Cox Fernandes, C.; Nogueira, A.; Williston, A. & Alves-Gomes, J.A. (2015). "A new species of electric knifefish from the Rio Negro, Amazon basin (Gymnotiformes: Hypopomidae, Microsternarchini)". Proceedings of the Academy of Natural Sciences of Philadelphia. 164 (1): 213–227. doi:10.1635/053.164.0113. S2CID 86768117.
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Family Hypopomidae". FishBase. May 2018 version.
- ^ Tagliacollo, V.A.; Bernt, M.J.; Craig, J.M.; Oliviera, C. & Albert, J.S. (2015). "Model-based Total Evidence phylogeny of Neotropical electric knifefishes (Teleostei, Gymnotiformes)". Molecular Phylogenetics and Evolution. 95: 20–33. doi:10.1016/j.ympev.2015.11.007. hdl:11449/168204. PMID 26616344.
- ^ Ferraris Jr, C.J.; C.D. de Santana & R.P. Vari (2017). "Checklist of Gymnotiformes (Osteichthyes: Ostariophysi) and catalogue of primary types". Neotropical Ichthyology. 15 (1): e160067. doi:10.1590/1982-0224-20160067.
- ^ van der Sleen, P. & J.S. Albert, eds. (2017). Field Guide to the Fishes of the Amazon, Orinoco, and Guianas. Princeton University Press. pp. 337–341. ISBN 978-0691170749.
- ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Hypopygus". Catalog of Fishes. California Academy of Sciences. Retrieved 3 June 2025.
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