''Steatogenys'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of gymnotiform knifefishes found in the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...

and Essequibo river basins in

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

South America. The widespread and common ''S. elegans'' is found in a wide range of habitats, from the shallow essentially static waters such as floodplain lakes to fast-flowing rivers as deep as . The two remaining species are less common and widespread, with ''A. duidae'' found mainly in small streams running through terra firme forests (forest that does not flood, unlike várzea) and ''S. ocellatus'' among submerged roots and branches in static or slow-flowing blackwater habitats. All three are regularly found among vegetation in floating meadows, a habitat that often contains little oxygen, but they are well-adapted to this. They are well-

camouflaged Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

and brown in color with a barred pattern. They resemble the related ''

Hypopygus ''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. They are often common, and found near submerged roots, aquatic vegetation and leaf-l ...

'', but are larger, reaching up to in total length depending on the exact species of ''Steatogenys''. They feed on invertebrates such as aquatic insect larvae and small shrimp.

Taxonomy and species

''Steatogenys'' has traditionally been included in the family

Hypopomidae The Hypopomidae are a family of fishes in the order Gymnotiformes known as the bluntnose knifefish. They may also be called grass or leaf knifefishes. These electric fish are not often eaten, of little commercial importance, rarely kept as aqu ...

, but a comprehensive molecular study from 2015 showed it belongs in Rhamphichthyidae, and this has been followed by recent authorities. There are currently three recognized species in this genus: * '' Steatogenys duidae'' ( La Monte, 1929) * '' Steatogenys elegans'' ( Steindachner, 1880) (Barred knifefish) * '' Steatogenys ocellatus'' Crampton,

Thorsen Thorson or Thorsen are Swedish, Norwegian and Danish surnames. Notable people with the surname include: Thorson *Charles Thorson (1890–1966), Canadian political cartoonist, character designer * Celeste Thorson, American actress, model writer, and ...

Albert Albert may refer to: Companies * Albert (supermarket), a supermarket chain in the Czech Republic * Albert Heijn, a supermarket chain in the Netherlands * Albert Market, a street market in The Gambia * Albert Productions, a record label * Alber ...

, 2004

References

Hypopomidae Freshwater fish of South America Freshwater fish genera Ray-finned fish genera Taxa named by George Albert Boulenger {{gymnotiformes-stub