''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. Most are from 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 technolog ...

basin, but ''S. orthos'' is found both in the Amazon and

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 wo ...

, ''S. orinoco'' is restricted to the Orinoco and ''S. curvioperculata'' restricted to the upper Paraná basin (however, the last species likely belongs in another genus, possibly ''

Apteronotus ''Apteronotus'' is a genus of weakly electric knifefish in the family Apteronotidae, distinguished by the presence of a tiny tail fin. This genus is restricted to tropical and subtropical South America (Amazon, Orinoco, Río de la Plata and ...

''). They are often common in their habitat.Lundberg, J.G., Cox Fernandes, C., Campos-Da-Paz, R. & Sullivan, J.P. (2013): ''Sternarchella calhamazon'' n. sp., the Amazon’s most abundant species of apteronotid electric fish, with a note on the taxonomic status of ''Sternarchus capanemae'' Steindachner, 1868 (Gymnotiformes, Apteronotidae). ''Proceedings of the Academy of Natural Sciences of Philadelphia, 162: 157-173.'' They have a blunt or pointed snout (none have the greatly elongated snout found in some other knifefish), reduced pigmentation and reach up to in total length depending on the species. They feed on invertebrates and small fish.

Species

The following species are currently placed in this genus. Two species that formerly comprised their own genus ''

Magosternarchus ''Magosternarchus'' is a genus of weakly electric knifefish in the family Apteronotidae, containing two species. They are endemic to Brazil, occurring in large river channels in the Amazon River basin. Both species are unusual benthic predator ...

'' were recently included in ''Sternarchella'' * ''

Sternarchella calhamazon ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Lundberg, Cox Fernandes, Campos-da-Paz &

Sullivan Sullivan may refer to: People Characters * Chloe Sullivan, from the television series ''Smallville'' * Colin Sullivan, a character in the film ''The Departed'', played by Matt Damon * Harry Sullivan (''Doctor Who''), from the British science f ...

, 2013 * ''

Sternarchella curvioperculata ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Godoy ( pt), 1968 – likely does not belong in this genus, closer to ''

'' * ''

Sternarchella duccis ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Lundberg, Cox Fernandes & Albert * ''

Sternarchella orinoco ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Mago-Leccia, 1994 * ''

Sternarchella patriciae ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Evans, Crampton & Albert 2017 * ''

Sternarchella raptor ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Lundberg, Cox Fernandes & Albert * ''

Sternarchella rex ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Evans, Crampton & Albert 2017 * ''

Sternarchella schotti ''Sternarchella schotti'' is a species of weakly electric knifefish in the family Apteronotidae. This species is endemic to Brazil where it is found in the Amazon River basin, and is sometimes kept in aquaria. The species grows to approximat ...

'' ( Steindachner, 1868) * ''

Sternarchella sima ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' Starks, 1913 * ''

Sternarchella terminalis ''Sternarchella'', the bulldog knifefish, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. ...

'' ( C. H. Eigenmann & W. R. Allen, 1942)

References

Apteronotidae Fish of South America Freshwater fish genera Taxa named by Carl H. Eigenmann {{Gymnotiformes-stub