Protopterus
Encyclopedia
The African lungfishes are the genus Protopterus and constitute the four species of lungfish
found in Africa
. Protopterus is the sole genus in the family Protopteridae.
-like fishes, with thread-like pectoral and pelvic fins. They have soft scales, and the dorsal
and tail fins are fused into a single structure. They can either swim like eels, or crawl along the bottom, using their pectoral and pelvic fins. The largest species reach about 200 centimetres (6.6 ft) long.
African lungfishes generally inhabit shallow waters such as swamps and marshes, however they are also found in larger lakes such as Lake Victoria
. They can live out of water for many months in burrows of hardened mud beneath a dried-up stream bed. They are carnivorous, eating crustacean
s, aquatic insect larvae, and molluscs.
The African lungfishes are obligate air breathers, with reduced gills in the adults. They have two anterior gill arches that retain gills, though they are too small to function as the sole respiratory apparatus. The lungfish heart has adaptations that partially separate the flow of blood into its pulmonary and systemic circuits. The atrium is partially divided, so that the left side receives oxygenated blood and the right side receives deoxygenated blood from the other tissues. These two blood streams remain mostly separate as they flow through the ventricle
leading to the gill arches. As a result oxygenated blood mostly goes to the anterior gill arches and the deoxygenated blood mostly goes to the posterior arches.
African lungfishes breed at the beginning of the rainy season. They construct nests or burrows in the mud to hold their eggs, which they then guard against predators. When they hatch, the young resemble tadpole
s, with external gills
, and only later develop lungs and begin to breath air.
s have been increasingly applied over the past fifty years, it is believed that the lungfish populations there are decreasing. In Uganda, females do not eat the lungfish because they consider it a "sister fish," and therefore it is associated with men and manhood.
Family Protopteridae
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
found in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. Protopterus is the sole genus in the family Protopteridae.
Description
African lungfishes are elongated, eelEel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
-like fishes, with thread-like pectoral and pelvic fins. They have soft scales, and the dorsal
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and tail fins are fused into a single structure. They can either swim like eels, or crawl along the bottom, using their pectoral and pelvic fins. The largest species reach about 200 centimetres (6.6 ft) long.
African lungfishes generally inhabit shallow waters such as swamps and marshes, however they are also found in larger lakes such as Lake Victoria
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
. They can live out of water for many months in burrows of hardened mud beneath a dried-up stream bed. They are carnivorous, eating crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, aquatic insect larvae, and molluscs.
Biology
The African lungfish is an example of how the evolutionary transition from breathing water to breathing air can happen. Lungfish are periodically exposed to water with low oxygen content or situations into which their aquatic environment dries up. Their adaptation for dealing with these conditions is an outpocketing of the gut, related to the swim bladder of other fishes, that serves as a lung. The lung contains many thin-walled blood vessels, so blood flowing through those vessels can pick up oxygen from air gulped into the lung.The African lungfishes are obligate air breathers, with reduced gills in the adults. They have two anterior gill arches that retain gills, though they are too small to function as the sole respiratory apparatus. The lungfish heart has adaptations that partially separate the flow of blood into its pulmonary and systemic circuits. The atrium is partially divided, so that the left side receives oxygenated blood and the right side receives deoxygenated blood from the other tissues. These two blood streams remain mostly separate as they flow through the ventricle
Ventricle (heart)
In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The Atria primes the Pump...
leading to the gill arches. As a result oxygenated blood mostly goes to the anterior gill arches and the deoxygenated blood mostly goes to the posterior arches.
African lungfishes breed at the beginning of the rainy season. They construct nests or burrows in the mud to hold their eggs, which they then guard against predators. When they hatch, the young resemble tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...
s, with external gills
External gills
External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits, as they are in most fishes. Instead, the respiratory organs are set on a frill of stalks protruding from the sides of an animals...
, and only later develop lungs and begin to breath air.
As food
Native Africans have been found to dig up lungfishes, burrow and all, and store it for later use when they want fresh fish to eat. These fish have also been carried in their mud burrows for exhibition in the United States. They have a strong taste. The taste is such that "it is locally either highly appreciated or strongly disliked". As technology advancements such as longlines and gillnetGillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
s have been increasingly applied over the past fifty years, it is believed that the lungfish populations there are decreasing. In Uganda, females do not eat the lungfish because they consider it a "sister fish," and therefore it is associated with men and manhood.
Species and subspecies
The family contains just four species:Family Protopteridae
- Protopterus aethiopicus HeckelJohann Jakob HeckelJohann Jakob Heckel was an Austrian taxidermist, zoologist, and ichthyologist from Mannheim.Though not a formally trained zoologist he worked his way up through the ranks to eventually become the director of the Fish Collection at the Naturhistorisches Museum in Vienna...
, 1851 - Marbled lungfish- Protopterus aethiopicus aethiopicus Heckel, 1851
- Protopterus aethiopicus congicus 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....
, 1961 - Protopterus aethiopicus mesmaekersi 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....
, 1961
- Protopterus amphibius (W. K. H. PetersWilhelm PetersWilhelm Karl Hartwich Peters was a German naturalist and explorer.He was assistant to Johannes Peter Müller and later curator of the Berlin Zoological Museum. In September 1842 he travelled to Mozambique via Angola. He returned to Berlin with an enormous collection of natural history specimens...
, 1844) - East African lungfish - Protopterus annectens (OwenRichard OwenSir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, 1839) - West African lungfish- Protopterus annectens annectens (Owen, 1839)
- Protopterus annectens brieni 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....
, 1961 - Southern lungfish
- Protopterus dolloi BoulengerGeorge Albert BoulengerGeorge Albert Boulenger FRS was a Belgian-British zoologist who identified over 2000 new animal species, chiefly fish, reptiles and amphibians.-Life:...
, 1900 - Slender lungfish or Spotted lungfish