Sturgeon

**Sturgeon** is the common name for 28 species of fish in the family **Acipenseridae**. The family has four extant genera: *Acipenser*, *Huso*, *Scaphirhynchus*, and *Pseudoscaphirhynchus*. Some species of sturgeon (for example, the beluga), are harvested for their valuable caviar.

## Description 
Sturgeons are known for their long body, which contains dozens of plates called scutes. They have a sharp snout and a heterocercal tail.

## Evolution 
Sturgeons have been referred to as "living fossils" or "primitive fish" because their features have not changed very much since their earliest fossil record.

### History 
Acipenseriformes first appeared 174–201 mya. Then, the "true" sturgeons appeared in the Upper Cretaceous.

### Taxonomy 
Family **Acipenseridae** (sturgeons)

* Genus *Acipenser* Linnaeus, 1758
** †*Acipenser albertensis* Lambe 1902 >
** *Acipenser baerii* J. F. Brandt, 1869 (Siberian sturgeon)
*** *Acipenser baerii baicalensis* A. M. Nikolskii, 1896 (Baikal sturgeon)
*** *Acipenser baerii stenorrhynchus* A. M. Nikolskii, 1896
** *Acipenser brevirostrum* Lesueur, 1818 (Shortnose sturgeon)
** *Acipenser dabryanus* A. H. A. Duméril, 1869 (Yangtze sturgeon)
** †*Acipenser cruciferus* (Cope 1876)
** †*Acipenser eruciferus* Cope 1876
** *Acipenser fulvescens* Rafinesque, 1817 (Lake sturgeon)
** †*Acipenser gigantissimus* Nessov 1997
** *Acipenser gueldenstaedtii* J. F. Brandt & Ratzeburg, 1833 (Russian sturgeon)
** *Acipenser medirostris* Ayres, 1854 (Green sturgeon)
** *Acipenser mikadoi* Hilgendorf, 1892 (Sakhalin sturgeon)
** †*Acipenser molassicus* Probst 1882
** *Acipenser naccarii* Bonaparte, 1836 (Adriatic sturgeon)
** *Acipenser nudiventris* Lovetsky, 1828 (Fringebarbel sturgeon)
** †*Acipenser ornatus* Leidy 1873
** *Acipenser oxyrinchus* Mitchill, 1815
*** *Acipenser oxyrinchus desotoi* Vladykov, 1955 (Gulf sturgeon)
*** *Acipenser oxyrinchus oxyrinchus* Mitchill, 1815 (Atlantic sturgeon)
** *Acipenser persicus* Borodin, 1897 (Persian sturgeon)
** *Acipenser ruthenus* Linnaeus, 1758 (Sterlet)
** *Acipenser schrenckii* J. F. Brandt, 1869 (Japanese sturgeon)
** *Acipenser sinensis* J. E. Gray, 1835 (Chinese sturgeon)
** *Acipenser stellatus* Pallas, 1771 (Starry sturgeon)
** *Acipenser sturio* Linnaeus, 1758 (European sea sturgeon)
** †*Acipenser toliapicus* Agassiz 1844 ex Woodward 1889
** *Acipenser transmontanus* J. Richardson, 1836 (White sturgeon)
** †*Acipenser tuberculosus* Probst 1882
* Genus *Huso* J. F. Brandt & Ratzeburg, 1833
** *Huso dauricus* (Georgi, 1775) (kaluga)
** *Huso huso* (Linnaeus, 1758) (beluga)
* Genus *Scaphirhynchus* Heckel, 1835
** *Scaphirhynchus albus* (Forbes & R. E. Richardson, 1905) (Pallid sturgeon)
** *Scaphirhynchus platorynchus* (Rafinesque, 1820) (Shovelnose sturgeon)
** *Scaphirhynchus suttkusi* J. D. Williams & Clemmer, 1991 (Alabama sturgeon)
* Genus *Pseudoscaphirhynchus* Nikolskii, 1900
** *Pseudoscaphirhynchus fedtschenkoi* (Kessler, 1872) (Syr Darya sturgeon)
** *Pseudoscaphirhynchus hermanni* (Kessler, 1877) (Dwarf sturgeon)
** *Pseudoscaphirhynchus kaufmanni* (Kessler, 1877) (Amu Darya sturgeon)

 (*Huso huso*)]]

## Habitat 
Sturgeon range from subtropical to subarctic waters in North America and Eurasia. In North America, they range along the Atlantic coast from the Gulf of Mexico to Newfoundland. They used to be found throughout the Mississippi River, the Great Lakes and the Hudson River.

Throughout this extensive range, almost all species are highly threatened or vulnerable to extinction due to a combination of habitat destruction, overfishing, and pollution.

In the last century, this large fish was often regarded as a nuisance because it often became entangled in and caused  commercial fishing nets to become ripped. Only much later did the sturgeon become prized for its meat, eggs (caviar) and oil. Gelatin from the inner lining of its air bladder was used to make isinglass–a substance used as a clarifying agent in jellies, glues and in the isinglass windows of carriages and early cars. Nowadays, the lake sturgeon's dark form can be sometimes be discerned in reedy shallows or near river mouths.

## Gallery 

File:Acipenser fulvescens GLERL.jpg|Lake sturgeon (*Acipenser fulvescens*)
File:Scaphirhynchus albus (Pallid sturgeon) FWS 23610.jpg|Pallid sturgeon (*Scaphirhynchus albus*)
File:Acipenser baerii.jpg|Siberian sturgeon (*Acipenser baerii*)

## References 
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## Other websites 
* Acipenser on the FishBase website
* https://www.wikidata.org/wiki/Q181871