''Mormyrus longirostris'', commonly referred as the eastern bottle-nosed mormyrid, is a medium-sized

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

belonging to the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Mormyridae The Mormyridae, sometimes called "elephantfish" (more properly freshwater elephantfish), are a family of weakly electric freshwater fish in the order Osteoglossiformes native to Africa. It is by far the largest family in the order with around 20 ...

. It was originally described by

Wilhelm Peters Wilhelm Karl Hartwich (or Hartwig) Peters (22 April 1815 in Koldenbüttel – 20 April 1883) was a German naturalist and explorer. He was assistant to the anatomist Johannes Peter Müller and later became curator of the Berlin Zoological Mus ...

in ''Monatsberichte der Akad. Wiss. Berlin'', 1852. This species grows to a maximum length of and can weigh up to . 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 c ...

is more than twice the length of 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 s ...

. The dorsal origin is nearer to the tip of the snout than to 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 s ...

base.

Ecology

It primarily feeds on weeds and

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s, but also on small

vertebrate Vertebrates () comprise all animal taxon, taxa within the subphylum Vertebrata () (chordates with vertebral column, backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the ...

s, such as small fish and

fish eggs Roe ( ) or hard roe is the fully ripe internal egg masses in the ovaries, or the released external egg masses, of fish and certain marine animals such as shrimp, scallop, sea urchins and squid. As a seafood, roe is used both as a cooked ing ...

. They hunt using electricity and can give a mild

electric shock Electrical injury is a physiological reaction caused by electric current passing through the body. The injury depends on the density of the current, tissue resistance and duration of contact. Very small currents may be imperceptible or produce a ...

to defend itself.

Range and habit

''M. longirostris'' can be found in abundance across the plains of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

in freshwater habitats, including the lower and middle

Zambezi The Zambezi River (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than hal ...

, lower Sabi and Ludi rivers and in the Luapula-Moero-Bangwelo (

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are ...

Congo Congo or The Congo may refer to either of two countries that border the Congo River in central Africa: * Democratic Republic of the Congo, the larger country to the southeast, capital Kinshasa, formerly known as Zaire, sometimes referred to a ...

system). It inhabits the

Ruvuma Ruvuma River, formerly also known as the Rovuma River, is a river in the African Great Lakes region. During the greater part of its course, it forms the border between Tanzania and Mozambique (in Mozambique known as ''Rio Rovuma''). The river is ...

and

Rufiji Rufiji may refer to: * Rufiji Delta, a region in Tanzania * Rufiji District, in the Pwani Region of Tanzania * Rufiji River, in Tanzania * Rufiji (ethnic group), of eastern Tanzania * Rufiji language Ndengereko, also known as Rufiji (Fiji, Rui ...

rivers in

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...

, lakes

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northe ...

Tanganyika Tanganyika may refer to: Places * Tanganyika Territory (1916–1961), a former British territory which preceded the sovereign state * Tanganyika (1961–1964), a sovereign state, comprising the mainland part of present-day Tanzania * Tanzania M ...

and

Rukwa Rukwa Region (''Mkoa wa Rukwa'' in Swahili) is one of Tanzania's 31 administrative regions with a postcode number 55000. The regional capital is the municipality of Sumbawanga. According to the 2012 national census, the region had a population o ...

and other eastward-flowing rivers in

. The species lives in caves and muddy areas with soft bottoms. It hides in weeds and characteristically forms small shoals.

Life history/behavior

Active mostly at night, it breeds during the summer

rainy season The rainy season is the time of year when most of a region's average annual rainfall occurs. Rainy Season may also refer to: * ''Rainy Season'' (short story), a 1989 short horror story by Stephen King * "Rainy Season", a 2018 song by Monni * '' ...

, moving upstream in rivers after water has receded, with migrations at irregular intervals. Females carry 10,000–70,000 eggs at a time.

Relationship to humans

The fish is harvested for food with bait and hook.

References

External links

* Mormyrus Freshwater fish of Africa Fish described in 1852 Taxa named by Wilhelm Peters {{osteoglossiformes-stub