African tetras

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African tetras
Blue Congo Tetra (Phenacogrammus interruptus) and Yellow Congo Tetra (Alestopetersius caudalis)

Blue Congo Tetra ( Phenacogrammus interruptus ) and Yellow Congo Tetra ( Alestopetersius caudalis )

Systematics
Overcohort : Clupeocephala
Cohort : Otomorpha
Sub-cohort : Ostariophysi
Otophysa
Order : Tetras (Characiformes)
Family : African tetras
Scientific name
Alestidae
Roberts , 1969

The African tetra (Alestidae, older spelling Alestiidae), also called bigeye tetra , are a family of the order of the tetra-like . The fish live in the fresh waters of tropical and subtropical Africa , most species come from the Congo river basin . Some species are very beautiful and popular freshwater ornamental fish .

features

Bigeye tetra have an elongated, sometimes slightly high-backed body that is covered with cycloid scales. Most species are large-eyed and have large dorsal fins. An adipose fin is present. The mouth is often slightly above. The animals have two rows of teeth on the premaxillary ( Bryconaethiops has three), the second with molar teeth ( Gr .: "Alestes" = to grind). The maxillary is toothless. African tetra of the former subfamily Alestinae are 3.2 to 60 centimeters long, the former Hydrocyninae reach lengths of half a to 1.35 meters. Specimens up to 1.50 meters have been caught in the giant tiger tetra .

Way of life

Most African tetras live as schooling fish in lakes and rivers. They feed primarily on insect larvae and other small aquatic life. Some species also eat plants. The large species of the Hydrocynus genus eat smaller fish. African tetras spawn in groups or in pairs in open water or between aquatic plants. The eggs sink to the bottom or stick to the plants.

Internal system

The internal systematics of the Alestidae according to Arroyave & Stiassny 2011
  Alestidae  

 Brycinus macrolepidotus species group


   


 Bryconaethiops


   

 Brycinus nurse species group



   


 Nannopetersius


   

 Bathyaethiops + Brachypetersius


   

 Clupeocharax + Phenacogrammus


   

 Alestopetersius + Tricuspidalestes





   

 Hydrocynus


   

 Alestes


   

 Bryconalestes


   

 Hemigrammopetersius  +  Rhabdalestes


   

 Ladigesia


   

 Micralestes










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The internal system of the African tetra is still controversial today. One suggestion is to place the large, piscivorous tiger fish ( Hydrocynus ) in a separate subfamily (Hydrocyninae) and all other African tetras in another (Alestinae), another four genera of large and medium-sized species ( Alestes, Brycinus, Bryconaethiops and Hydrocynus ) in one tribe (Alestiini) and the smaller ones in another (Petersiini). For the latter, the absence of a multi-pointed, molar-shaped dentition and the pronounced sexual dimorphism present in many species are given as a feature . The toothing is considered to be the original feature but cannot be used to clarify the internal relationships between the subgroups.

The right Kladogramm detected by the comparison of two markers of mitochondrial and nuclear - DNA , results in the evaluation of the data sets on the principle of maximum parsimony (Parsimony). If they are calculated using the Bayesian statistics method, the result is almost the same cladogram, only Alestes and Hydrocynus are then sister genera . DNA of the genera Petersius and Virilia were not available.

For two more, monotypic genera with the African Großschuppensalmler ( Arnoldichthys spilopterus ) and the Adonis Tetra ( Lepidarchus adonis ) as a species that calculations showed they apparently did not belong to the Alestidae but the South American in a large clade tetras are, the African Großschuppensalmler as a relative the American pike tetra (Ctenoluciidae), the Adoniss tetra basal to a clade of Chalceus , the Acestrorhynchidae and the real tetras (Characidae).

Genera and species

A total of about 115 species belong to the African tetras.

literature

  • Günther Sterba : Freshwater fish in the world . Urania Verlag., Leipzig 1990; Licensed edition for Weltbild Verlag GmbH, Augsburg 1995, ISBN 3-89350-991-7 .
  • Melanie Stiassny, Guy Teugels & Carl D. Hopkins: The Fresh and Brackish Water Fishes of Lower Guinea, West-Central Africa, Volume 1. ISBN 9789074752206 .

Individual evidence

  1. ↑ a b c Jairo Arroyave, Melanie LJ Stiassny: Phylogenetic relationships and the temporal context for the diversification of African characins of the family Alestidae (Ostariophysi: Characiformes): Evidence from DNA sequence data. Molecular Phylogenetics and Evolution, Volume 60, Issue 3, September 2011, doi: 10.1016 / j.ympev.2011.04.016
  2. ↑ Stiassny, Teugels & Hopkins (2007), pp. 381-383.
  3. ↑ Fricke et al .: Eschmeyer's Catalog of Fishes: Genera, Species, References. Accessed July 30, 2020 .
  4. ↑ Mbimbi MM, JJ & Stiassny, MLJ (2012): A new Alestopetersius (Characiformes: Alestidae) from the Kwilu River (Kasai basin) of central Africa; with a phylogeny for the genus and synonymy of Duboisialestes . Zootaxa , 3166: 59-68. PDF
  5. ↑ a b Paugy, D .: Révision systématique des Alestes et Brycinus africains (Pisces, Characidae). Collection Etudes et Théses. Editions de l'ORSTOM, Paris., 1986 ( ird.fr [PDF]).
  6. ^ Zanata, AM and RP Vari (2005): The family Alestidae (Ostariophysi, Characiformes): a phylogenetic analysis of a trans-Atlantic clade. Zoological Journal of the Linnean Society v. 145: 1-144.

Web links

Commons : African tetra  - Collection of images, videos and audio files