Bichir
Encyclopedia
The bichirs are a family, Polypteridae, of archaic-looking ray-finned fishes
, the sole family in the order
Polypteriformes.
All species occur in freshwater habitats in tropical Africa and the Nile
River system, mainly swampy, shallow floodplain
s and estuaries
.
structure more closely resembles that of the tetrapod
s than that of the teleost fishes. Bichirs have a number of other primitive characteristics, including fleshy pectoral fins superficially similar to those of lobe-finned fishes
. They also have a pair of slit-like spiracle
s used to exhale air, two gular plates and double ventral lung
s (the left lung smaller than the right), which allow them to obtain oxygen from the air when in poorly oxygenated waters, by swimming quickly to the surface and back to the bottom. They are nocturnal, and feed on small vertebrates, crustaceans, and insects. Four pairs of gill arches are present.
Bichirs have a maximum body length of 97 centimetres (3.2 ft).
. Though predatory, they are otherwise peaceful and relatively nonactive, preferring to lie on the bottom, and make good tank-mates with other species that are large enough not to be prey. Some aquarists note that Loricariid
catfish and common Plecostomus
may attack bichirs and suck on their skin.
Order Polypteriformes
Extinct species include:
Actinopterygii
The Actinopterygii or ray-finned fishes constitute a class or sub-class of the bony fishes.The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines , as opposed to the fleshy, lobed fins that characterize...
, the sole family in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Polypteriformes.
All species occur in freshwater habitats in tropical Africa and the Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...
River system, mainly swampy, shallow floodplain
Floodplain
A floodplain, or flood plain, is a flat or nearly flat land adjacent a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge...
s and estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
.
Anatomy and appearance
Bichirs are elongated fish with a unique, subdivided series of dorsal finlets which varies in number from seven to eighteen, instead of a single dorsal fin. Each of the dorsal finlets have bifid (doubleedged) tips, and are the only fins with spines, the rest of the fins being composed of soft rays. The body is covered in thick, bonelike and trapezoidal ganoid scales. Their jawJaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
structure more closely resembles that of the tetrapod
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...
s than that of the teleost fishes. Bichirs have a number of other primitive characteristics, including fleshy pectoral fins superficially similar to those of lobe-finned fishes
Sarcopterygii
The Sarcopterygii or lobe-finned fishes – sometimes considered synonymous with Crossopterygii constitute a clade of the bony fishes, though a strict classification would include the terrestrial vertebrates...
. They also have a pair of slit-like spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s used to exhale air, two gular plates and double ventral lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s (the left lung smaller than the right), which allow them to obtain oxygen from the air when in poorly oxygenated waters, by swimming quickly to the surface and back to the bottom. They are nocturnal, and feed on small vertebrates, crustaceans, and insects. Four pairs of gill arches are present.
Bichirs have a maximum body length of 97 centimetres (3.2 ft).
Bichirs as aquarium specimens
Bichirs are popular subjects of public and large hobby aquariaAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
. Though predatory, they are otherwise peaceful and relatively nonactive, preferring to lie on the bottom, and make good tank-mates with other species that are large enough not to be prey. Some aquarists note that Loricariid
Loricariidae
Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...
catfish and common Plecostomus
Plecostomus
Hypostomus plecostomus is the scientific name for a type of freshwater tropical Central and South American fish belonging to the family Loricariidae. They are large algae eaters, and to differentiate them from small algae eaters, they are often referred to as plecostomus, often abbreviated as...
may attack bichirs and suck on their skin.
Species
There are twelve extant species in two genera:- Family Polypteridae
- Genus Erpetoichthys J. A. Smith, 1865
- Erpetoichthys calabaricus J. A. Smith, 1865 (Reedfish)
- Genus PolypterusPolypterusPolypterus is a genus of freshwater fish in the bichir family of order Polypteriformes. The type species is the Nile bichir . Fishes in this genus live in various areas in Africa...
Lacépède, 1803- Retropinnis Group
- Polypterus retropinnis Vaillant, 1899 (West African bichir)
- Bichir Group
- Polypterus ansorgiiPolypterus ansorgiiPolypterus ansorgii, commonly called Guinean Bichir, is a bony fish from rivers and other freshwater habitats in Western Africa, ranging from Guinea-Bissau to Nigeria. It reaches a maximum length of , is greenish-brown to black in color and has large, dark spots and blotches on its flanks. On...
BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1910 (Guinean bichir) - Polypterus bichirPolypterus bichirPolypterus bichir is also known as the Nile bichir, is a fish which lives in the Nile River, Africa, and some of its tributaries.- Description :...
Lacépède, 1803 (Nile bichir)- Polypterus bichir bichir Lacepède, 1803
- Polypterus bichir katangae PollMax PollMax Fernand Leon Poll was a Belgian ichthyologist who specialised in Cichlidae.In the years 1946 and 1947 he organised an expedition to Lake Tanganyika....
, 1941 (Most likely variant of Polypterus congicus) - Polypterus bichir lapradei SteindachnerFranz SteindachnerFranz Steindachner was an Austrian zoologist.- Work and career :Being interested in natural history, Steindachner took up the study of fossil fishes on the recommendation of his friend Eduard Suess...
, 1869
- Polypterus congicus BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1898 (Congo bichir) - Polypterus endlicheri Heckel, 1847 (Saddled bichir)
- Polypterus ansorgii
- Weeksii Group
- Polypterus mokelembembe Schliewen & Schäfer, 2006 (Mokèlé-mbèmbé bichir)
- Polypterus ornatipinnis BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1902 (Ornate bichir) - Polypterus weeksii BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1898 (Mottled bichir)
- Senegalus Group
- Polypterus delheziPolypterus delheziThe armoured bichir or banded bichir is a snake-like fish that ranges from the Congo River, specifically in the upper and middle portions. This species is one of the more commonly available in commercial pet stores.....
BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1899 (Barred bichir) - Polypterus palmas AyresWilliam Orville AyresWilliam Orville Ayres was an American physician and ichthyologist. Born in Connecticut, he studied to become a doctor at Yale University School of Medicine....
, 1850 (Shortfin bichir)- Polypterus palmas buettikoferi SteindachnerFranz SteindachnerFranz Steindachner was an Austrian zoologist.- Work and career :Being interested in natural history, Steindachner took up the study of fossil fishes on the recommendation of his friend Eduard Suess...
, 1891 - Polypterus palmas palmas Ayres, 1850
- Polypterus palmas polli J. P. Gosse, 1988
- Polypterus palmas buettikoferi Steindachner
- Polypterus senegalus CuvierGeorges CuvierGeorges Chrétien Léopold Dagobert Cuvier or Jean Léopold Nicolas Frédéric Cuvier , known as Georges Cuvier, was a French naturalist and zoologist...
, 1829 (Gray bichir)- Polypterus senegalus meridionalis PollMax PollMax Fernand Leon Poll was a Belgian ichthyologist who specialised in Cichlidae.In the years 1946 and 1947 he organised an expedition to Lake Tanganyika....
, 1941 (Most likely variant of Polypterus senegalus senegalus) - Polypterus senegalus senegalus Cuvier, 1829
- Polypterus senegalus meridionalis Poll
- Polypterus teugelsi Britz, 2004 (Cross River bichir)
- Polypterus delhezi
- Retropinnis Group
- Genus Erpetoichthys J. A. Smith, 1865
Extinct species include:
- Polypterus faraou Otero et al., 2006 — late MioceneMioceneThe Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
.