African multi-spined

from Wikipedia, the free encyclopedia
African multi-spined
Polycentropsis abbreviata 2.jpg

African multi-spined ( Polycentropsis abbreviata )

Systematics
Perch relatives (Percomorphaceae)
Ovalentaria
incertae sedis
Family : Many spines (Polycentridae)
Genre : Polycentropsis
Type : African multi-spined
Scientific name of the  genus
Polycentropsis
Boulenger , 1901
Scientific name of the  species
Polycentropsis abbreviata
Boulenger, 1901

The African multi-spined ( Polycentropsis abbreviata ) is one of three known representatives of the multi-spined in Africa , whose systematic position is viewed differently.

features

The appearance corresponds to that of a typical squid . African spines are high-backed, have a large head and a large mouth with a deeply cut, very flexible mouth. Sexually mature specimens reach overall lengths between six and eight centimeters. Like all sea bass, this species also has a pronounced ability to change colors. The mostly piebald body color varies from a dark ocher yellow to a reddish brown to almost pure black. Within a few moments, colors and drawing patterns can change at will, which means that the fish can react to rapidly changing light conditions and maintain its camouflage. Only three dark bands that run from the eye towards the tip of the snout, the attachment of the dorsal fin and the lower edge of the gill cover are always visible. The hard-radiating parts of the dorsal and anal fin are clearly jagged. With the exception of the pectoral fins and the soft rayed part of the dorsal fin, which are each transparent, the body coloration continues in the fins. With the exception of the laying tube of the females, which is clearly visible during spawning, no other external sex characteristic is known.

ecology

Knowledge of this tropical freshwater fish , its origin and way of life is sparse. WJ Ansorge brought the first preserved specimens from his Niger expedition to England . Boulenger named in the first description of these documents as the type locality "Junction of Ethiop River and Jamieson River, Niger Delta". All other African multi-spines deposited in museums come from Nigeria , Gabon , Cameroon and Benin . But in 1974 the Republic of Burundi issued a series of stamps with native fish species, one of which also shows Polycentropsis abbreviata , and in 2004 the species appeared in a list of fish from the tropical rainforest of Guinea . The distribution area outlined in the literature with West Africa reflects the current incomplete state of knowledge. Apparently, the species inhabits bank and flood zones of slowly flowing and stagnant water in shaded rainforest areas. There it lives in the vegetation zone and is hidden between aquatic plants, roots or dead wood. As lurking and suddenly attacking predators , well-camouflaged African multi- spined animals stand in their cover and move very slowly with barely discernible fin movements. As their English popular name “African Leaf-Fish” expresses, the fish imitate a vertically drifting leaf ( mimetic ). Their food, which must stimulate movement, consists of larger insect larvae , small crustaceans , tadpoles and other fish. The prey is acquired by suddenly opening the large mouth, creating a vacuum that pulls the prey into the strongly toothed mouth.

Reproduction

Knowledge of reproductive behavior is based solely on a few aquarium observations. Male African spines woo females ready to reproduce by building one or more foam nests on the underside of aquatic plant leaves . To do this, they only use air taken in from the surface of the water, which they expel under the leaves as fine bubbles through the gill covers. These air bubbles are not, as is the case with labyrinth fish , coated with secretion formed in the mouth. This is why these nests only last for a short time and have to be constantly renewed. Spawning does not take place in these first foam nests, but on the underside of another nearby leaf. To do this, the female turns on her back after a short courtship and attaches the eggs to the substrate with the sticky pole . Now the male stands in a normal swimming position, trembling next to the female, expelling sperm and fanning them towards the eggs. Then the female returns to her normal body position. This process is repeated various times until the clutch consists of between 100 and 200 eggs and is complete. Now the male embeds the spawn in foam bubbles and guards and fanning the clutch alone. The larvae hatch after about five days and attach to leaves in the immediate vicinity of the nest. After a further 24 hours they swim freely. Once they have left the nest, the males' brood care operation ceases .

Systematics

At the end of the 19th century, WJ Ansorge brought thousands of botanical and zoological specimens to Europe from expeditions through West and Central Africa . From the fish collection handed over to the British Museum of Natural History in 1899 , Boulenger described Polycentropsis abbreviata in 1901 as a member of the sea bass family ( Nandidae ). Synonym descriptions were not given. The Nandidae originally comprised seven genera of perch-like freshwater fish. In 1967 Barlow hived off the blue bass into its own Badidae family . In 1970 Liem separated the scallop perch , for which Roberts created the Pristolepididae family in 1989 . In the Nandidae the genera Nandus , Afronandus , Polycentropsis , Polycentrus and Monocirrhus remained . On the basis of a work published by Britz in 1997 on the morphology of the eggs of sea bass, very considerable differences emerged. The 0.7 to 0.8 mm small eggs of the nandus species that do not care for the brood carry the adhesive organ on the animal egg pole. In all other genera, the organs of attachment are located on the vegetative pole of the eggs between 1.1 and 1.8 mm in size, whereby Monocirrhus occupies a special position in that its eggs stick to the substrate on short stalks. The investigations by Britz led to further insights into polyphyly and to a renewed subdivision of the Nandidae, which now only includes the South and Southeast Asian rhea species. Afronandus , Polycentropsis , Polycentrus and Monocirrhus now form the family of the African and American polyhedra, the Polycentridae .

Importance to humans

In West Africa, African multi-spined fish are a small part of the yield of the fish traps that are common there. In the freshwater aquarium hobby, the fish that Hans Stüve brought to Europe alive for the first time in 1906 plays a minor outsider role. Only very few specialists maintain the irregularly imported species, which is why it was only very rarely bred.

swell

  • Roberts TR, (1975): Geographical distribution of African freshwater fishes . Zoological Journal of the Linnaean Society, 57: 249-319.
  • Thys van den Audenaerde, DFE & J. Breine (1986): Nandidae : 342-343. In Daget, J., Gosse, J.-P. & DFE Thys van den Audenaerde (eds.): Check-list of the freshwater fishes of Africa (CLOFFA) . ISBN, Brussels; MRAC, Tervuren; and ORSTOM, Paris. Vol. 2.
  • Skelton, PH (1988): The distribution of African freshwater fishes : 65-91. In: C. Lévêque, Bruton, MN & GW Ssentongo (eds.): Biology and ecology of African freshwater fishes . ORSTOM, Paris.
  • Lévêque, C., Paugy, D. & GG Teugels (1991): Annotated check-list of the freshwater fishes of the Nilo-sudan river basins, in Africa . Rev. Hydrobiol. Trop. 24 (2): 131-154.
  • Kamdem-Toham, A. &. GG Teugels (1997): Patterns of microhabitat use among fourteen abundant fishes of the lower Ntem River Basin Cameroon . Aquatic Living Resources, 10: 289-298
  • Mdaihli, M., du Feu, T. & JSO Ayeni (2003): Fisheries in the southern border zone of Takamanda Forest Reserve, Cameroon : 141-154. In: Takamanda: the Biodiversity of an African forest . SI / MAB Ser. 8th.

Individual evidence

  1. ↑ Brummet, RE & GG Teugels (2004): Rivers of the lower Guinean rainforest: Biogeography and sustainable Exploitation . In: Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries Volume I. Welcomme R. and T. Petr, Eds., FAO Regional Office for Asia and the Pacific, Bangkok, Thailand. RAP Publication 2004/16149 - 171.
  2. ↑ Britz, R. & R. Rucksack (1997): On the reproductive biology of the sea bass and blue perch . D. Aqu. u. Terr. Z. (DATZ) 53 (5): 18-21 & 53 (6): 10-14.
  3. ^ Ansorge, WJ (1899): Under the African Sun; A Description of Native Races in Uganda, Sporting Adventures and Other Experiences . London, William Heinemann.
  4. ↑ Boulenger, GA (1901): On the fishes collected by Dr. WJ Ansorge in the Niger Delta. Proceedings of the General Meetings for Scientific Business of the Zoological Society of London 1901, v. 1 (pt 1): 4-10, Pls. 2-4.
  5. ↑ Barlow, GW, Liem, KF & Wickler, W. (1968): Badidae, a new fish family. The behavioral, osteological and developmental evidence . Journal of Zoology, London 156: 415-447.
  6. ↑ Liem, KF (1970): Comperative functional anatomy of the Nandidae . Fieldiana Zool. 56: 1-166.
  7. ^ Roberts, T. (1989): The Freshwater fishes of western Borneo (Kalimantan Barat, Indonesia) . Mem. Cal. Acad. Sci. 14th
  8. ↑ Britz, R. (1997): Egg surface structure and larval cement glands in nandid and badid fishes (Teleostei, Percomorpha), with remarks on phylogeny and zoogeography . American Museum Novitates 3195: 1-17.

Web links

Commons : Polycentropsis abbreviata  - Collection of images, videos and audio files