Gasterosteus

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Gasterosteus
Three-spined stickleback (Gasterosteus aculeatus)

Three-spined stickleback ( Gasterosteus aculeatus )

Systematics
Perch relatives (Percomorphaceae)
Order : Perch-like (Perciformes)
Subordination : Cottoidei
Partial order : Sticklebacks (Gasterosteales)
Family : Sticklebacks (Gasterosteidae)
Genre : Gasterosteus
Scientific name
Gasterosteus
Linnaeus , 1758

Gasterosteus is a genus of sticklebacks . Their representatives colonize a wide range of habitats in salt water as well as in brackish and fresh water . They can be found in large parts of the northern hemisphere , but do not penetrate as far into arctic regions as the sticklebacks of the genus Pungitius . The main area of ​​distribution is along the sea coasts in the marine area. Type species is the three-spined stickleback and Europa terra typica .

features

The relatively small fish are relatively variable in size and side signs, the differences are partly genetically determined, but are also subject to strong ecological influences. The marine and anadromous forms are usually larger and slimmer than pure freshwater populations. In front of the soft-rayed dorsal fin, there are three, rarely four, dorsal spines on bone plates along the middle of the back. The first two spines are long and strong, the rear spine is significantly smaller. The absolute length of the spines is subject to strong fluctuations. Another powerful sting sits on each ventral fin . The ventral spines are supported against the massive pelvic girdle. The latter consists of the pelvic bones ( ossa pubis ) that have grown together to form a large abdominal shield , the elongated wings of which are connected to the neighboring side and back shields. At the beginning of the anal fin there is another, shorter spine. A row of bone plates covers each side of the body. They reach their greatest vertical extent in the abdominal region, the smallest shields are at the beginning of the caudal peduncle, which carries keeled plates.

Within the Gasterosteidae , the Gasterosteus have developed the most efficient defensive armament with their reduced number but very efficient spines and robust signage. This allows them to live a more open way of life compared to other members of their family, which is expressed, among other things, by staying in areas with little cover and a very conspicuous spawning color of the males.

Systematics

At the time of their definition by Linnaeus , the genus Gasterosteus was also assigned the nine-spined and sea ​​stickleback . These two species were later raised to the rank of their own genera. The taxonomic record of Gasterosteus is extremely difficult. At times over 40 different population groups had species rank. With the exception of Gasterosteus wheatlandi , these groups were later merged as conspecific under the "superspecies" Gasterosteus aculeatus . In the 1990s some taxa were revalidated by Kottelat . The associated division of the European three-spined stickleback into a fully signposted species with a marine distribution focus, G. aculeatus , and a less signposted species with a predominantly inland habitat in Western Europe, Gasterosteus gymnurus , is rejected by Paepke . He argues that the distribution of the freshwater habitats of G. gymnurus cannot be reconciled with the fact that all three-spined sticklebacks reached their inland habitats through river systems coming from the coast and the species is therefore polyphyletic . In jointly inhabited areas, small and fully signposted forms mate without restriction with fertile offspring. Paepke regards the revalidated species Gasterosteus islandicus as polyphyletic for the same reasons.

Some populations that may reach species status have not yet been scientifically described. Examples of this are the "white stickleback" in Nova Scotia and shapes from Lake Ashabachye on Kamchatka .

supporting documents

  1. ↑ a b c d e Petru M. Bănărescu, Hans-Joachim Paepke: The Freshwater Fishes of Europe , Aula-Verlag, Wiebelsheim 2002, ISBN 3-89104-658-8 . (Volume 5. Cyprinidae 2, Part III: Carassius to Cyprinus; Gastorosteidae) pp. 206-208
  2. ↑ Hans-Joachim Paepke: The sticklebacks: Gasterosteidae , Westarp Wissenschaften, Magdeburg 1996, ISBN 3-89432-492-9 , p. 100.
  3. ↑ a b c Paepke p. 88
  4. ↑ a b Paepke p. 91,92
  5. ↑ Hans-Joachim Paepke: About the nest building techniques of sticklebacks In: Aquaristik-Fachmagazin Jg. 40, No. 202, 2008, ISSN  1437-4854 , p. 48,49
  6. ↑ Maurice Kottelat, Jörg Freyhof: Handbook of European freshwater fishes . Kottelat and Freyhof, Cornol (Switzerland) and Berlin 2007, ISBN 978-2-8399-0298-4 . Pp. 492-496.
  7. ↑ Higuchi, M., Sakai, H. & Goto, A. (2014): A new threespine stickleback, Gasterosteus nipponicus sp. nov. (Teleostei: Gasterosteidae), from the Japan Sea region. Ichthyological Research, November 2014, Volume 61, Issue 4, Pages 341–351, DOI: 10.1007 / s10228-014-0403-1

Web links

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