Disruptive

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Disruptive
Chondrosteus (= Strongylosteus) hindenburgi from the Lower Jurassic from Holzmaden in the Stuttgart Natural History Museum

Chondrosteus (= Strongylosteus) hindenburgi from the Lower Jurassic from Holzmaden in the Stuttgart Natural History Museum

Systematics
Trunk : Chordates (chordata)
Sub-stem : Vertebrates (vertebrata)
Superclass : Jaw mouths (Gnathostomata)
Class : Ray fins (Actinopterygii)
Subclass : Cartilage organoids (chondrostei)
Order : Disruptive
Scientific name
Acipenseriformes
Berg , 1940

The order sturgeon (Acipenseriformes) or "cartilage smelting" includes two still existing ( recent ) families of bony fish with 30 species and several fossil groups. They represent the only recent representatives of the cartilaginous organoids , a more or less diverse group of original bony fish, depending on the definition. Sturgeon species have been known as fossils since the Jurassic , possibly even since the Permian .

features

The sturgeon have an incompletely ossified skeleton and the scales of the trunk are greatly or completely reduced. Another important feature is the reduction of the dermal bones of the maxillary and premaxillary as well as the hyostyle and thus highly mobile suspension of the palatoquadratum, the cartilaginous “primordial skeleton” of the upper jaw and palate. These transformations are related to a strongly soil-related diet of the animals.

Tribal history, oldest representatives and systematics

Peipiaosteus pani (Upper Jurassic)
Yanosteus longidorsalis
Shovel sturgeon ( Scaphirhynchus platorynchus )
Paddlefish ( Polyodon spathula )
Crossopholis magnicaudatus

The Acipenseriformes represent a very early branch of the line that leads to the modern bony fish, the teleosts. Their closest fossil relatives are the Birgeriidae , a group that is traditionally assigned to the " Palaeonisciformes ". The latter are considered to be representatives of the first great radiation of bony fish in the Upper Paleozoic.

Acipenseriformes have been proven to be fossilized since the Lower Jurassic. The species Chondrosteus acipenseroides from the Sinemurian and Hettangian from southwest and central England is one of the historically longest known fossil sturgeon species. Another early Jurassic species, Strongylosteus hindenburgi from the Posidonia schist ( Toarcium ) from Holzmaden in Baden-Württemberg, may also belong to the genus Chondrosteus .

In 2005 a fossil was described from China that could extend the stratigraphic range of the sturgeon-like even into the Upper Permian. The representative with the name Euchondrosteus sinenis comes from the Fangshankou formation of the Gansu province .

Currently there are only two families left of the sturgeon-like sturgeon , the sturgeon (Acipenseridae) with 25 species in four genera and the dipper (Polyodontidae) with 2 species in two genera.

The system of the Acipenseriformes is given in the following list:

Danger

All recent species are endangered and at least locally extinct. The World Sturgeon Conservation Society is particularly committed to protecting these species . Some are of great economic importance as edible fish and, above all, as suppliers of caviar .

Individual evidence

  1. ↑ a b c d William E. Bemis, Eric K. Findeis, Lance Grande: An overview of Acipenseriformes. Environmental Biology of Fishes. Vol. 48, No. 1-4, 1997, pp. 25-71, doi : 10.1023 / A: 1007370213924
  2. ^ Lu Liwu, Li Daqing, Yang Liangfeng: Notes on the discovery of Permian Acipenseriformes in China. Chinese Science Bulletin. Vol. 50, No. 12, 2005, pp. 1279-1280, doi : 10.1007 / BF03183706
  3. ^ Integrated Taxonomic Information System

literature

  • Kurt Fiedler: Textbook of Special Zoology, Volume II, Part 2: Fish. Gustav Fischer Verlag, Jena 1991, ISBN 3-334-00339-6
  • Joseph S. Nelson: Fishes of the World. John Wiley & Sons, 2006, ISBN 0-471-25031-7
  • Juraj Holcik: The Freshwater Fishes of Europe. Vol. 1 / II, AULA-Verlag, Wiesbaden 1989, ISBN 3-89104-431-3
  • Lance Grande, William E. Bemis: Osteology and phylogenetic relationships of fossil and recent paddlefishes (Polyodontidae) with comments on the interrelationships of Acipenseriformes. Society of Vertebrate Paleontology Memoir. Vol. 1, 1991, 122 pp.

Web links

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