Apteronotus

Apteronotus es un género de peces cuchillo débilmente eléctricos de la familia Apteronotidae , que se distingue por la presencia de una pequeña aleta caudal . Este género está restringido a Sudamérica tropical y subtropical ( cuencas del Amazonas , Orinoco , Río de la Plata y Magdalena , así como ríos del oeste de Colombia y las Guayanas ) y Panamá , donde se encuentra en una amplia gama de hábitats de agua dulce. ^{[ 2 ] [ 3 ]} Se alimentan de pequeños animales. ^{[ 2 ]}

Depending on the exact species, they reach a total length of up to about 18–50 cm (7–20 in). Although it has been claimed that A. magdalenensis is up to 130 cm (4.3 ft) long, this is not supported by recent studies and likely the result of confusion with Sternopygus aequilabiatus.^[2][4] 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.^[2] The last group is not closely related to the first two and will likely need to be moved to another genus.^[3][5] A genetic study published in 2019 found that the genus is strongly polyphyletic with several groups that are quite distantly related.^[6]

Apteronotus contains the following recognized species:^[7]

• Apteronotus acidopsTriques, 2011
• Apteronotus albertoiPeixoto, Dutra, Datovo, Menezes & de Santana, 2021
• Apteronotus albifrons(Linnaeus, 1766) (Black ghost knifefish)
• Apteronotus anude Santana & Vari, 2013
• Apteronotus apurensisFernández-Yépez, 1968
• Apteronotus baniwade Santana & Vari, 2013
• Apteronotus bonapartii(Castelnau, 1855)
• Apteronotus brasiliensis(J. T. Reinhardt, 1852)
• Apteronotus camposdapazide Santana & Lehmann-A., 2006
• Apteronotus caudimaculosusde Santana 2003
• Apteronotus cuchillejo(Schultz, 1949)
• Apteronotus cuchilloSchultz, 1949
• Apteronotus ellisi(Alonso de Arámburu, 1957)
• Apteronotus eschmeyeri de Santana, Maldenado-Ocampo , Severi y GN Mendes , 2004
• Apteronotus ferrarisi de Santana & Vari, 2013
• Apteronotus galvisi de Santana, Maldonado-Ocampo & Crampton , 2007
• Apteronotus jurubidae ( Fowler , 1944)
• Apteronotus leptorhynchus ( MM Ellis , )1912 (Pez cuchillo fantasma marrón)
• Apteronotus lindalvae de Santana & Cox Fernandes , 2012
• Apteronotus macrolepis ( Steindachner , 1881)
• Apteronotus macrostomus (Fowler, 1943)
• Apteronotus magdalenensis ( Miles , 1945)
• Apteronotus magoi de Santana, Castillo G. & Taphorn , 2006
• Apteronotus mariae ( CH Eigenmann & Fisher , 1914)
• Apteronotus milesi de Santana & Maldonado-Ocampo, 2005
• Apteronotus paranaensis ( Schindler , 1940)
• Apteronotus pemón de Santana & Vari, 2013
• Apteronotus quilombola Peixoto, Datovo, Menezes & de Santana, 2021
• Apteronotus rostratus ( Meek & Hildebrand , 1913)
• Apteronotus spurrellii ( Regan , 1914)

El siguiente cladograma se basa en un estudio filogenético de 2019 que analiza secuencias de genes mitocondriales y nucleares de Apteronotidae. Cabe destacar que Apteronotus , tal como se define tradicionalmente, no es monofilético, como se observa aquí; ^{[ 6 ]}