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Micralestes acutidens

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII CHARACIFORMES ALESTIDAE

Scientific Name: Micralestes acutidens
Species Authority: (Peters, 1852)
Common Name(s):
English Elongated Robber, Sharptooth tetra, Sharptooth tetra (FB), Silver robber, Silver tetra
Synonym(s):
Alestes acutidens Peters, 1852
Brachyalestes acutidens (Peters, 1852)
Micralestes acutidens neglectus (Boulenger, 1920)
Micralestes brevianalis Blache & Miton, 1960
Micralestes humilis (non Boulenger, 1899)
Micralestes luluae Fowler, 1930
Micralestes neglectus (Boulenger, 1920)
Petersius neglectus Boulenger, 1920
Virilia brevianalis (Blache & Miton, 1960)
Taxonomic Notes: Micralestes acutidens is most similar to M. elongatus, from which it differs in the presence of multicuspid (vs. conical, monocuspid) inner dentary teeth, inner premaxillary and outer dentary teeth with greater number of cusps, and a slightly more robust body. Paugy (1990:80) has questioned the reported occurrence of this species in Nilo-Sudanic and West African drainages and, on the basis of the presence of conical inner dentary teeth, instead regards the form in these regions as M. elongatus. He does not, however, question the diagnostic utility of mono- versus multicuspid inner dentary teeth for differentiating these two species. Such a determination must await a thorough revisionary study and detailed comparison of the material from the Niger and Cross basins, the region of putative sympatry of these species.
The population close to the source of the Zambezi is morphologically distinct, being larger and less deep than fish elsewhere in its range. The fish have red fins compared to the colourless or creamy fins of those elsewhere. This requires taxonomic investigation (Tweddle et al. 2004).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2010
Date Assessed: 2009-05-01
Assessor(s): Azeroual, A., Bills, R., Cambray, J., Entsua-Mensah, M., Hanssens, M., Lalèyè, P., Marshall, B. & Moelants, T.
Reviewer(s): Snoeks, J., Tweddle, D., Getahun, A., Lalèyè, P., Paugy, D., Zaiss, R., Fishar, M.R.A & Brooks, E.
Justification:
This species has a wide distribution, with no known major widespread threats. It is therefore listed as Least Concern. It has also been assessed regionally as Least Concern for central, eastern, north eastern and southern Africa. The species used to be known (and caught) from Luxor and Aswan region of Egypt in the Nile. The impacts of the Aswan High Dam and pollution are thought to have caused this extirpation, and it is now assessed as Regionally Extinct within north Africa. There is no immigration of individuals from outside the region (above the High Dam).

Geographic Range [top]

Range Description: This is a widespread species, found from Sudan to South Africa, and westerly as far as east Nigeria.

Central Africa: Micralestes acutidens is known from throughout the Congo River basin, including Lakes Kariba and Tanganyika. In Lower Guinea it is found in the Cross and Sanaga Rivers.

Eastern Africa: It is present in the Lower Shire (Tweddle and Willoughby 1979) and Rovuma Rivers.

Northern Africa: It used in to be found and caught from Luxor and Aswan in Egyptian Nile, but is now extirpated from the region.

Northeast Africa: This species is present in the Ghazal el Jebel systems, White Nile.

Southern Africa: It is known from Congo and Zambezi systems, including the Cunene and Okavango, and east coast rivers south to the Phongolo (Skelton 2001). This species is the only characin found in the northern tributaries of the upper Zambezi system in Zambia (Tweddle et al. 2004).
Countries:
Native:
Angola (Angola); Botswana; Cameroon; Central African Republic; Congo; Congo, The Democratic Republic of the; Malawi; Mozambique; Namibia; Nigeria; South Africa; South Sudan; Sudan; Swaziland; Zambia; Zimbabwe
Regionally extinct:
Egypt
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Limited information. Numerous in suitable habitats.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Micralestes acutidens is a pelagic, potamodromous species. It forms shoals in clear, flowing or standing, open water. Common in water with fringing vegetation. It appears to co-exist with the tigerfish Hydrocynus forskalii in open water although it is heavily preyed upon by that predator, particularly those shoals of tigerfish ranging up to 45 cm in length (Bell-Cross and Minshull 1988). Omnivorous, often feeding from surface waters on winged insects. Also takes insect larvae, crustaceans and eggs and fry of other fish (Bell-Cross and Minshull 1988). They mature after a year. A partial spawner of moderate fecundity, with usually fewer than 700 eggs per female. Shoals migrate upstream after first summer rains; breeds throughout the summer months. Used as forage fish and as bait for tigerfish and pike (Skelton 1993).
Systems: Freshwater

Use and Trade [top]

Use and Trade: This species is used as bait for tigerfish.

Threats [top]

Major Threat(s): This species is threatened by overfishing with small meshed gears.

Conservation Actions [top]

Conservation Actions: The species has some protection in reserves such as Kafue National Park. More research is needed into this species taxonomy, and biology and ecology, as well as monitoring of population trends.

Citation: Azeroual, A., Bills, R., Cambray, J., Entsua-Mensah, M., Hanssens, M., Lalèyè, P., Marshall, B. & Moelants, T. 2010. Micralestes acutidens. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 16 September 2014.
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