African pike tetra

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African pike tetra
Hepsetus lineatus from the Dja in southern Cameroon.

Hepsetus lineatus from the Dja in southern Cameroon .

Systematics
Cohort : Otomorpha
Sub-cohort : Ostariophysi
Otophysa
Order : Tetras (Characiformes)
Family : Hepsetidae
Genre : African pike tetra
Scientific name of the  family
Hepsetidae
Greenwood , Rosen , Weitzman & Myers , 1966
Scientific name of the  genus
Hepsetus
Swainson , 1838

The African pike tetra ( Hepsetus ) are a genus of predatory fish from the order of the characiformes and the only genus of the Hepsetidae family. It is widespread in western, central and southern Africa. Their habitat ranges from Senegal in the west to Angola in the south and includes the river basins of the Kunene , Okavango , Kafue and the upper Zambezi . It is absent in the Nile and in East Africa with the African Great Lakes .

features

African pike tetra have an elongated, pike-like body covered by cycloid scales and are a maximum of 30 centimeters long. They are barely flattened on the sides and have a flat top on the head. The muzzle is long, the mouth large and occupied by some very large, conical and rearward-facing fangs and smaller, pointed teeth. There are sail-like attachments on the jaw that may be sensory organs . The top of the fish is brownish, the flanks and belly are silvery with a clay-yellow tinge. The eyes are large and brass-colored, the nostrils are close together. They have a red-orange spot above the eyes, behind which there are some light and dark bands. The fins are pink to gray, the dorsal fin has some brown-red rays, the adipose fin is black. Adult animals can have black spots on the paired fins. The anal fin lies behind the dorsal fin. African pike tetra have 45 to 49 vertebrae . There are 49 to 60 scales along the lateral line organ .

African pike tetra are relatively short-lived and only live to be three to five years old.

Way of life

They are loners and loyal ambulance hunters . Young fish hide in plant stocks, while adult animals tend to lurk in deeper water above the open ground. They feed primarily on fish and can overwhelm prey that can reach 40% of their own size. The young fish eat insects and their larvae.

African pike tetra migrate to smaller tributaries and flooded areas during spawning time and build reproductive nests out of foam and plant material that are guarded by one or both parents. A female can lay 10,000 eggs.

External system

The position of the African pike tetra in the zoological system has not yet been finally clarified. In a scientific work from 2005, the family was identified as a sister group of a clade of slender tetras (Lebiasinidae) and American pike tetras (Ctenoluciidae). The sister group of all three families together were the African tetras (Alestidae). A study from 2011, on the other hand, identified the Hepsetidae as a sister group of the Alestidae, while in one of the most extensive studies of recent times from 2018 the genus Hepsetus is even embedded in the Alestidae.

species

The pike tetra population from the upper Congo could represent another, previously undescribed species.

Research history

The first species of the genus was described in 1794 by the German naturalist and doctor Marcus Élieser Bloch as Salmo odoe , i.e. as salmon , the genus was established in 1838 by the Englishman William Swainson , and the Hepsetidae family in 1966 by the British ichthyologist Peter Humphry Greenwood and colleagues. Another species was described in 1861 by the French explorer Francis de La Porte de Castelnau as Hydrocyonoides cuvieri , but was synonymous with Hepsetus odoe in 1984 . In 2011, Hepsetus cuvieri was revalidated and in 2013 two more species were newly described. The species are differentiated according to morphological features, such as the scale formula, number and arrangement of the teeth and the gill trap rays.

literature

  • E. Decru, E. Vreven, J. Snoeks: A revision of the West African Hepsetus (Characiformes: Hepsetidae) with a description of Hepsetus akawo sp. nov. and a redescription of Hepsetus odoe (Bloch, 1794). In: Journal of Natural History. Vol. 45, No. 27-28, 2011, pp. 1723-1744. doi: 10.1080 / 00222933.2011.622055 .
  • E. Decru, J. Snoeks, E. Vreven: The true identity of the holotype of Hepsetus odoe and the names of the two West African species of Hepsetus (Teleostei: Hepsetidae). In: Ichthyological Exploration of Freshwaters. Volume 24, No. 2, 2013, pp. 187-192.
  • Axel Zarske: "Hepsetus Swainson, 1838" and "Hepsetus odoe (Bloch, 1794)" African pike tetra. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 472.

Individual evidence

  1. ↑ D. Calcagnotto, S. Schaefer, R. DeSalle: Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences. In: Molecular Phylogenetics and Evolution. Vol. 36, No. 1, July 2005, pp. 135-153 doi: 10.1016 / j.ympev.2005.01.004
  2. ↑ Oliveira et al. 2011: Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling. BMC Evolutionary Biology v. 11 (no. 275): 1-25. doi : 10.1186 / 1471-2148-11-275
  3. ↑ Mirande, JM 2018: Morphology, molecules and the phylogeny of Characidae (Teleostei, Characiformes). Cladistics, 35: 282-300. doi : 10.1111 / cla.12345
  4. Jump up ↑ TA Zengeya, E. Decru, E. Vreven: Revalidation of Hepsetus cuvieri (Castelnau) (Characiformes: Hepsetidae) from the Quanza, Zambezi and southern part of the Congo ichthyofaunal provinces. In: Journal of Natural History. Vol. 45, No. 27-28, 2011, pp. 1723-1744. doi: 10.1080 / 00222933.2011.560724
  5. ^ E. Decru, E. Vreven, J. Snoeks: A revision of the Lower Guinean Hepsetus species (Characiformes; Hepsetidae) with the description of Hepsetus kingsleyae sp. nov. In: Journal of Fish Biology. Volume 82, 2013, pp. 1351-1375. doi: 10.1111 / jfb.12079
  6. ↑ E. Decru, J. Snoeks, E. Vreven: Taxonomic evaluation of the Hepsetus from the Congo basin with the revalidation of H. microlepis (Teleostei: Hepsetidae). In: Ichthyological Exploration of Freshwaters. Volume 26, No. 3, 2015, pp. 273–287.

Web links

Commons : Hepsetus  - collection of pictures, videos and audio files