Featherback

The family Notopteridae contains 11 species of osteoglossiform (bony-tongued) fishes, commonly known as featherbacks and knifefishes. These fishes live in freshwater or brackish environments in Africa and West Asia, West, South Asia, South, East Asia, East and Southeast Asia.

With the denotation of "knifefish", the notopterids should not be confused with Gymnotiformes, the electric knifefishes from South and Central America. Although their manner of swimming is similar and they are superficially similar in appearance, the two groups are not closely related.

A few of the larger species, especially ''Chitala ornata'', are food fish and occasionally aquarium pets. The name is from Greek language, Greek ''noton'' meaning "back" and ''pteron'' meaning "fin".

Fossils

The earliest fossil of this family is otolith of ''Notopteridarum'' from the Late Cretaceous of India, about 70.6 to 66 million years ago.

Description

Featherbacks have slender, elongated, bodies, giving them a knife-like appearance. The caudal fin is small and fused with the anal fin, which runs most of the length of the body. Where present, the dorsal fin is small and narrow, giving rise to the common name of "featherback". The fish swims by holding its body rigid and rippling the anal fin to propel itself forward or backwards.

Notopterids have specialized swim bladders. The organ extends throughout the body and even into the fins in some cases. Although the swim bladder is not highly vascularised, it can absorb oxygen from air and also functions to produce sound by squeezing air through a narrow passage into the pharynx.

At least some species prepare nests and guard the eggs until they hatch.

Species

The 10 species in four genera are:
* Subfamily Xenomystinae Greenwood 1963 (African knifefishes, African featherbacks)
** Genus ''Papyrocranus'' Humphry Greenwood, Greenwood, 1963
*** ''Papyrocranus afer'' (Albert Günther, Günther, 1868) (reticulated knifefish)
*** ''Papyrocranus congoensis'' (John Treadwell Nichols, Nichols & Francesca Raimonde La Monte, La Monte, 1932)
** Genus ''Xenomystus'' Albert Günther, Günther, 1868
*** ''Xenomystus nigri'' (Albert Günther, Günther, 1868) (African brown knifefish)
* Subfamily Notopterinae Bleeker 1851 (Asian knifefishes, Asian featherbacks)
** Genus ''Chitala'' Henry Weed Fowler, Fowler, 1934
*** ''Chitala blanci'' (François d'Aubenton-Carafa, d'Aubenton, 1965) (royal knifefish or Indochina featherback)
*** ''Chitala borneensis'' (Pieter Bleeker, Bleeker, 1851) (Indonesian featherback)
*** ''Chitala chitala'' (Francis Buchanan-Hamilton, F. Hamilton, 1822) (Indian featherback)
*** ''Chitala hypselonotus'' (Pieter Bleeker, Bleeker, 1852)
*** ''Chitala lopis'' (Pieter Bleeker, Bleeker, 1851) (giant featherback)
*** ''Chitala ornata'' (John Edward Gray, J. E. Gray, 1831) (clown featherback or clown knifefish)
** Genus ''Notopterus'' Bernard Germain de Lacépède, Lacépède, 1800 (bronze featherbacks)
*** ''Notopterus notopterus'' (Peter Simon Pallas, Pallas, 1769) (Southeast Asia populations)
*** ''Notopterus synurus'' (Bloch & Schneider, 1801) (South Asia populations)

References

Further reading

* Berra, Tim M. (2001). ''Freshwater Fish Distribution''. San Diego: Academic Press.

The historical biogeography of the freshwater knifefishes.

{{Taxonbar, from=Q446602

Notopteridae,
Fish of Africa
Fish of Southeast Asia
Teleostei families
Extant Maastrichtian first appearances