Mormyroidea
   HOME



picture info

Mormyroidea
The Mormyroidea (synonymy: Mormyriformes) are a superfamily (formerly an order) of fresh water fishes endemic to Africa that, together with the families ''Hiodontidae, Osteoglossidae, Pantodontidae'' and ''Notopteridae'', represents one of the main groups of living Osteoglossiformes. They stand out for their use of weak electric fields, which they use to orient themselves, reproduce, feed, and communicate. There is no consensus regarding its superior biological classification as some experts state that it belongs to the suborder '' Osteoglossoidei'', while others to the '' Notopteroidei''. In either case, the mormyriformes include the gymnarchids and mormyrids and represent the largest superfamily within the order ''Osteoglossiformes'' with about two hundred and thirty-three subordinate taxa that are distributed across various watersheds existing throughout tropical Africa south of the Sahara, including the Nile, Turkana, Gambia, and northern South Africa. These fish have a ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Gymnarchus
The African knifefish, ''Gymnarchus niloticus'' – also called the ''aba aba'' – is an electric fish, living at the bottoms of rivers and lakes. It is the only species in the genus ''Gymnarchus'' and the family Gymnarchidae, within the order Osteoglossiformes. It is a long slender fish with no pelvic or anal fins, and a tail fin shaped like a rat's tail. It swims using its elongated dorsal fin, allowing it to keep its body straight while it moves. This in turn enables it to produce a steady but weak electric field, which it uses to locate its prey. It is large for a river fish; adults can reach 1.6 m (5.2 ft) in length and 19 kg (42 lb) in weight. In 1950, Hans Lissmann noticed that the fish could swim equally well forwards or backwards, clearly relying on a sense other than vision. He demonstrated that it could locate prey by electroreception, making it the first fish known to have this ability. The fish is considered good to eat in West Africa, wh ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Osteoglossiformes
Osteoglossiformes , meaning "bony tongues" in Ancient Greek, 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 South America, Africa, Australia and southern Asia, having first evolved in Gondwana before that continent broke up. In 2008, several new species of marine osteoglossiforms were described from the Danish Eocene Fur Formation, dramatically increasing the diversity of this group. This implies that the Osteoglossomorpha is not a primary freshwater fish group with the osteoglossiforms having a typical Gondwana distribution. The Gymnarchidae (the only species being '' Gymnarchus niloticus'', the African knifefish) and the Mormyridae are weakly electric fish able to sense their prey using electric fields. The mooneyes (Hiodontidae) are often classified here, but may also be placed in a separate order, Hiodontiformes. Members ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Electroreception And Electrogenesis
Electroreception and electrogenesis are the closely related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes, such as the electric eel, to stun prey. The capabilities are found almost exclusively in aquatic or amphibious animals, since water is a much better conductor of electricity than air. In passive electrolocation, objects such as prey are detected by sensing the electric fields they create. In active electrolocation, fish generate a weak electric field and sense the different distortions of that field created by objects that conduct or resist electricity. Active electrolocation is practised by two groups of weakly electric fish, the order Gymnotiformes (knifefishes) and family Mormyridae (elephantfishes), and by the monotypic genus '' Gymnarchus'' (African knifefish). An electric fish generates an electric field using an electric organ, mod ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Mormyridae
The Mormyridae, sometimes called "elephantfish" (more properly freshwater elephantfish), are a superfamily of weakly electric fish in the order Osteoglossiformes native to Africa. It is by far the largest family in the order, with around 200 species. Members of the family can be popular, if challenging, aquarium species. These fish have a large brain size and unusually high intelligence. They are not to be confused with the marine and brackish-water callorhinchid elephantfish (family Callorhinchidae) of Southern Hemisphere oceans. Description and biology The elephantfish are a diverse family, with a wide range of different sizes and shapes. The smallest are just in adult length, while the largest reach up to . They do, however, have a number of unique features in common. Firstly, their cerebellum is greatly enlarged, enabling them to interpret complex bio-electrical signals, and to the large size of the valve. Secondly, an auditory vesicle (a small bladder) is present insid ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Electric Organ (fish)
file:Elektroplax_Rochen.png, An electric ray (Torpediniformes) showing location of paired electric organs in the head, and electrocytes stacked within it In biology, the electric organ is an organ (biology), organ that an electric fish uses to create an electric field. Electric organs are derived from modified muscle or in some cases nerve tissue, called electrocytes, and have evolved at least six times among the Elasmobranchii, elasmobranchs and teleosts. These fish use their electric discharges for animal navigation, navigation, communication, mating, defence in animals, defence, and in strongly electric fish also for the incapacitation of Predation, prey. The electric organs of two strongly electric fish, the Electric ray, torpedo ray and the electric eel, were first studied in the 1770s by John Walsh (scientist), John Walsh, Hugh Williamson, and John Hunter (surgeon), John Hunter. Charles Darwin used them as an instance of convergent evolution in his 1859 ''On the Origin of S ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Notopteroidei
Notopteroidei is a suborder of the order Osteoglossiformes that contains the extant families Gymnarchidae (aba), Notopteridae (feather backs and knifefish) and Mormyridae (elephantfishes), as well as several extinct taxa. The Mormyridae are weakly electric fish An electric fish is any fish that can Bioelectrogenesis, generate electric fields, whether to sense things around them, for defence, or to stun prey. Most fish able to produce shocks are also electroreceptive, meaning that they can sense electric ...es, able to locate prey in turbid water. References Osteoglossiformes Ray-finned fish suborders {{Osteoglossiformes-stub ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Lake Turkana
Lake Turkana () is a saline lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. By volume it is the world's fourth-largest salt lake after the Caspian Sea, Issyk-Kul, and Lake Van (passing the shrinking South Aral Sea), and among all lakes it ranks 24th. Lake Turkana is now threatened by the construction of the Gilgel Gibe III Dam in Ethiopia due to the damming of the Omo river which supplies most of the lake's water. Although the lake commonly has been—and to some degree still is—used for drinking water, its salinity (slightly brackish) and very high levels of fluoride (much higher than in fluoridated water) generally make it unsuitable for drinking directly, and it has also been a source of diseases spread by contaminated water. Increasingly, communities on the lake's shores rely on underground springs for drinking water. The ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Sahara
The Sahara (, ) is a desert spanning across North Africa. With an area of , it is the largest hot desert in the world and the list of deserts by area, third-largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic. The name "Sahara" is derived from , a broken plural form of ( ), meaning "desert". The desert covers much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile, Nile Valley in Egypt and the Sudan. It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south it is bounded by the Sahel, a belt of Tropical and subtropical grasslands, savannas, and shrublands, semi-arid tropical savanna around the Niger River valley and the Sudan (region), Sudan region of sub-Saharan Africa. The Sahara can be divided into several regions, including ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Nile
The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river systems by length, longest river in the world, though this has been contested by research suggesting that the Amazon River is slightly longer.Amazon Longer Than Nile River, Scientists Say
Of the world's major rivers, the Nile has one of the lowest average annual flow rates. About long, its drainage basin covers eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, Sudan, and Egypt. In pa ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Albert Günther
Albert Karl Ludwig Gotthilf Günther , also Albert Charles Lewis Gotthilf Günther (3October 18301February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile taxonomist (after George Albert Boulenger) with more than 340 reptile species described. Early life and career Günther was born in Esslingen in Swabia ( Württemberg). His father was a ''Stiftungs-Commissar'' in Esslingen and his mother was Eleonora Nagel. He initially schooled at the Stuttgart Gymnasium. His family wished him to train for the ministry of the Lutheran Church for which he moved to the University of Tübingen. A brother shifted from theology to medicine, and he, too, turned to science and medicine at Tübingen in 1852. His first work was "''Ueber den Puppenzustand eines Distoma''" (On the pupal state of ''Distoma''). He graduated in medicine with an M.D. from Tübingen in 1858, the same year in which he published a handbook ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Gambia
The Gambia, officially the Republic of The Gambia, is a country in West Africa. Geographically, The Gambia is the List of African countries by area, smallest country in continental Africa; it is surrounded by Senegal on all sides except for the western part, which is bordered by the Atlantic Ocean.Hoare, Ben. (2002) ''The Kingfisher A–Z Encyclopedia'', Kingfisher Publications. p. 11. . Its territory is on both sides of the lower reaches of the Gambia River, which flows through the centre of the country and empties into the Atlantic. The national namesake river demarcates the elongated shape of the country, which has an area of and a population of 2,769,075 people in 2024 which is a 47% population increase from 2013. The capital city is Banjul, which has the most extensive metropolitan area in the country. The second and third-largest cities are Serekunda and Brikama. Arab Muslims, Arab Muslim merchants traded with indigenous West Africans in The Gambia throughout the 9th ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Drainage Basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern. Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, " watershed" is used only in its original sense, that of the drainage divide line. A drainage basin's boundaries are determined by watershed delineation, a common task in environmental engineering and science. In a closed drainage basin, or endorheic basin, rather than flowing to the ocean, water converges toward the ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]