Apteronotus Cuchillejo

''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 Magdalena basins, as well as rivers in western Colombia and the Guianas) and Panama where found in a wide range of freshwater habitats. They feed on small animals.

Depending on the exact species, they reach a total length of up to about . Although it has been claimed that ''A. magdalenensis'' is up to long, this is not supported by recent studies and likely the result of confusion with ''Sternopygus aequilabiatus''. Members of ''Apteronotus'' fall into three species groups based on their morphology: the ''A. albifrons'' group have a rounded snout and are black or dark brown with a contrasting light stripe on the top of the head, and bands on the tail and at its base, the ''A. leptorhynchus'' group have an elongate, slender snout (especially in males) and are brown with a light stripe along the head and back, and a band on the tail, and the ''A. bonapartii'' group have an elongate (males) or rounded (females) snout and are brown or gray (capable of some color change) with a light band on the tail. The last group is not closely related to the first two and will likely need to be moved to another genus. A genetic study published in 2019 found that the genus is strongly polyphyletic with several groups that are quite distantly related.

Species

There are currently 27 recognized species in this genus:
* ''Apteronotus acidops'' Triques, 2011Triques, M.L. (2011): Apteronotus acidops, ''new species of long snouted electric fish (Teleostei: Gymnotiformes: Apteronotidae) from the upper rio Paraná basin in Brazil, with a key to the apteronotid species from the area.'' Vertebrate Zoology, 61 (3): 299–306.
* ''Apteronotus albifrons'' ( Linnaeus, 1766) (Black ghost knifefish)
* ''Apteronotus anu'' de Santana & Vari, 2013de Santana, C.D. & Vari, R.P. (2013): Brown ghost electric fishes of the ''Apteronotus leptorhynchus'' species-group (Ostariophysi, Gymnotiformes); monophyly, major clades, and revision. ''Zoological Journal of the Linnean Society, 168 (3): 564–596.''
* ''Apteronotus apurensis'' Fernández-Yépez, 1968
* ''Apteronotus baniwa'' de Santana & Vari, 2013
* ''Apteronotus bonapartii'' ( Castelnau, 1855)
* ''Apteronotus brasiliensis'' ( J. T. Reinhardt, 1852)
* '' Apteronotus camposdapazi'' de Santana & Lehmann-A., 2006
* '' Apteronotus caudimaculosus'' de Santana, 2003
* '' Apteronotus cuchillejo'' ( L. P. Schultz, 1949)
* '' Apteronotus cuchillo'' L. P. Schultz, 1949
* ''Apteronotus ellisi'' ( Alonso de Arámburu, 1957)
* '' Apteronotus eschmeyeri'' de Santana, Maldenado-Ocampo, Severi & G. N. Mendes, 2004
* '' Apteronotus ferrarisi'' de Santana & Vari, 2013
* '' Apteronotus galvisi'' de Santana, Maldenado-Ocampo & Crampton, 2007
* '' Apteronotus jurubidae'' ( Fowler, 1944)
* '' Apteronotus leptorhynchus'' ( M. M. Ellis, 1912) (Brown ghost knifefish)
* ''Apteronotus lindalvae'' de Santana & Cox Fernandes, 2012de Santana, C.D. & Cox Fernandes, C. (2012): A New Species of Sexually Dimorphic Electric Knifefish from the Amazon Basin, Brazil (Gymnotiformes: Apteronotidae). ''Copeia, 2012 (2): 283-292.''
* '' Apteronotus macrolepis'' (Steindachner, 1881)
* '' Apteronotus macrostomus'' ( Fowler, 1943)
* '' Apteronotus magdalenensis'' (Miles, 1945)
* '' Apteronotus magoi'' de Santana, Castillo G. & Taphorn, 2006
* ''Apteronotus mariae'' ( C. H. Eigenmann & Fisher, 1914)
* ''Apteronotus milesi'' de Santana & Maldenado-Ocampo, 2005
* '' Apteronotus pemon'' de Santana & Vari, 2013
* '' Apteronotus rostratus'' ( Meek & Hildebrand, 1913)
* '' Apteronotus spurrellii'' (Regan, 1914)

References

{{Taxonbar, from=Q2859065

Apteronotidae
Freshwater fish of South America
Taxa named by Bernard Germain de Lacépède
Freshwater fish genera