The family Notopteridae contains 10 species of

osteoglossiform Osteoglossiformes (Greek: "bony tongues") is a relatively primitive order of ray-finned fish that contains two sub-orders, the Osteoglossoidei and the Notopteroidei. All of at least 245 living species inhabit freshwater. They are found in Sou ...

(bony-tongued) fishes, commonly known as featherbacks and knifefishes. These fishes live in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

environments in Africa and

South South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

. With the denotation of "knifefish", the notopterids should not be confused with

Gymnotiformes The Gymnotiformes are an order of teleost bony fishes commonly known as Neotropical knifefish or South American knifefish. They have long bodies and swim using undulations of their elongated anal fin. Found almost exclusively in fresh water (the ...

, 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 Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''noton'' meaning "back" and ''pteron'' meaning "fin".

Fossils

The earliest fossils of this family are of '' Notopteridarum'' and ''

Notopterus The bronze featherback (''Notopterus notopterus''; as, কান্ধুলি ''kandhuli'', bn, ফলি, bn, কাংলা,, th, ปลาสลาด, ปลาฉลาด, ปลาตอง, Vietnamese: ''Cá thát lát'', my, င� ...

'' from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

, about 70.6 to 66 million years ago. These fossils originate from the Rangapur microvertebrate site and Naskal microvertebrate site of

Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...

, which are part of the

Intertrappean Beds The Intertrappean Beds are a Late Cretaceous geologic formation in India. The beds are found as interbeds between Deccan Traps layers. Indeterminate theropod and pterosaur remains have been recovered from the formation, as well as dinosaur eggs ...

Description

Featherbacks have slender, elongated, bodies, giving them a knife-like appearance. The

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is small and fused with the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

, which runs most of the length of the body. Where present, the

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

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 The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

. 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 ** Genus ''

Papyrocranus ''Papyrocranus'' is a genus of freshwater fishes in family Notopteridae found in Middle and West Africa. Species * ''Papyrocranus afer'' ( Günther, 1868) (reticulated knifefish) * ''Papyrocranus congoensis'' (Nichols Nichols may refer to: Peo ...

'' Greenwood, 1963 *** ''

Papyrocranus afer The reticulated knifefish (''Papyrocranus afer'') is a species of freshwater fish in the family Notopteridae, the featherbacks, found in tropical West Africa. It reaches a maximum length of and a reported weight of . Description The reticulated ...

'' ( Günther, 1868) (reticulated knifefish) *** ''

Papyrocranus congoensis ''Papyrocranus congoensis'' is a species of ray-finned fish in the family Notopteridae found in the Congo River The Congo River ( kg, Nzâdi Kôngo, french: Fleuve Congo, pt, Rio Congo), formerly also known as the Zaire River, is the second ...

'' (

Nichols Nichols may refer to: People *Nichols (surname) *Nichol, a surname Places Canada * Nichols Islands, Nunavut United States * Nichols, California, an unincorporated community * Nichols Canyon, Los Angeles, California * Nichols, Connecticut * Nich ...

& La Monte, 1932) ** Genus ''Xenomystus'' Günther, 1868 *** ''

Xenomystus nigri The African brown knifefish (''Xenomystus nigri''), is the only species in the genus ''Xenomystus'' of the family Notopteridae. This fish is found in the Lake Chad, Chad, Nile River, Nile, Congo River, Congo, Ogooué River, Ogowe and Niger River ...

'' ( Günther, 1868) (African knifefish) * Subfamily Notopterinae Bleeker 1851 (Asian knifefishes, featherbacks) ** Genus ''

Chitala ''Chitala'' is a genus of fish of the family Notopteridae. This genus contains six species, in which some are important in aquaculture and the aquarium industry. They are commonly known as the Asian knifefishes or featherbacks. They are native to ...

'' Fowler, 1934 *** ''

Chitala blanci The royal knifefish or Indochina featherback, ''Chitala blanci'', is a species of ray-finned fish in the family Notopteridae found in the Mekong basin in Cambodia, Laos, Thailand and Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), off ...

'' ( d'Aubenton, 1965) (royal knifefish or Indochina featherback) *** ''

Chitala borneensis The Indonesian featherback (''Chitala borneensis'') is a species of knifefish from freshwater habitats in Southeast Asia. The details of its range are not entirely clear, with FishBase reporting that it occurs in Sumatra, Borneo, and the Mala ...

'' (

Bleeker Bleeker is a Dutch occupational surname. Bleeker is an old spelling of ''(linnen)bleker'' ("linen bleacher").Chitala chitala ''Chitala chitala'' (Assamese: চিতল ''sitawl'', Bengali: চিতল, ''chitol'') is a knifefish from Bangladesh, India, Nepal, and Pakistan, found in the Brahmaputra, Indus, Ganges and Mahanadi River basins. It is sometimes known as ...

'' ( F. Hamilton, 1822) (Indian featherback) *** ''

Chitala hypselonotus ''Chitala hypselonotus'' is a species of knifefish found in freshwater habitats in Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, i ...

'' (

Bleeker Bleeker is a Dutch occupational surname. Bleeker is an old spelling of ''(linnen)bleker'' ("linen bleacher").Chitala lopis ''Chitala lopis'', locally known as the belido, is an extinct species of freshwater fish, formerly endemic to the islands of Java and Sumatra in Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia an ...

'' (

Bleeker Bleeker is a Dutch occupational surname. Bleeker is an old spelling of ''(linnen)bleker'' ("linen bleacher").Chitala ornata The clown featherback, clown knifefish, or spotted knifefish, ''Chitala ornata'', is a nocturnal tropical fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, Laos, Thailand, and Vietnam, but it has al ...

'' (

J. E. Gray John Edward Gray, Fellow of the Royal Society, FRS (12 February 1800 – 7 March 1875) was a British zoology, zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ...

, 1831) (clown featherback or clown knifefish) ** Genus ''Notopterus'' Lacépède, 1800 *** '' Notopterus notopterus'' (

Pallas Pallas may refer to: Astronomy * 2 Pallas asteroid ** Pallas family, a group of asteroids that includes 2 Pallas * Pallas (crater), a crater on Earth's moon Mythology * Pallas (Giant), a son of Uranus and Gaia, killed and flayed by Athena * Pa ...

, 1769) (bronze featherback)

Fossils

Description

Species

References

Further reading