Hypopomidae — Details

learn more about names for this taxon

Wikipedia

Hypopomidae

Learn more about this article

Hypopomidae is a family of fishes in the order Gymnotiformes known as the bluntnose knifefish. They may also be called grass or leaf knifefishes.[1] These fish are not often eaten, of little commercial importances, are rarely kept as aquarium fish, and are poorly studied; however, species in this family may constitute a significant fraction of the biomass to the areas they inhabit.[2]

These fish originate from freshwater in Panama and South America.[1] The Hypopomidae is confined to the Humid Neotropics, ranging the Río de la Plata of Argentina (35° S) to the Río Tuira of Panama (8°N). Hypopomids are known from the continental waters of all South American countries except Chile, and are most diverse in the Amazon Basin.[2]

Description

The teeth are absent on the oral jaws. Unlike the closely related Rhamphichthyidae, species of this family do not have a tubular snout, but a blunt, short one:). Also, the nostrils are well separated. This family contains the smallest gymnotiform, Hypopygus lepturus, which reaches a maximum of 9 centimetres (3.5 in) TL. The largest species in this family reaches only 35 centimetres (14 in) in Brachyhypopomus brevirostris.[1] These fish have extremely small eyes that are smaller in diameter than the distance between their nares. The long anal fin originates below or posterior to their pectoral fins. There is no caudal fin.[2]

The electric organ discharge (EOD) of these fish are multiphasic (usually biphasic), and are produced in distinct pulses.[2] Certain predators, such as catfish and predatory knifefish, are able to detect these EODs and use this to their advantage in finding prey. However, it has been found that species in the genus Brachyhypopomus restrict the low-frequency spectrum of their electric field close to their body, allowing higher-frequencies to spread further; this makes it more difficult for predators to detect them.[3]

Species

There are 20 species of bluntnose knifefish, grouped into seven genera:[4]

References

  1. ^ a b c Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc.. ISBN 0-471-25031-7. 
  2. ^ a b c d Froese, Rainer, and Daniel Pauly, eds. (2007). "Hypopomidae" in FishBase. Apr 2007 version.
  3. ^ Stoddard, Philip K.; Markham, Michael R. (2008). "Signal Cloaking by Electric Fish". BioScience 58 (5): 415–425. doi:10.1641/B580508. PMC 2832175. PMID 20209064. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2832175. 
  4. ^ Froese, Rainer, and Daniel Pauly, eds. (2011). "Hypopomidae" in FishBase. December 2011 version.
Wikispecies has information related to: Hypopomidae
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

 

Source: Wikipedia

Unreviewed

Article rating from 0 people

Average rating: 2.5 of 5

Comment on or rate this article

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!