Gar
From Wikipedia, the free encyclopedia
| Gar Fossil range: Late Cretaceous–Recent [1] |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Lepisosteiformes Hay, 1929 |
| Family: | Lepisosteidae Cuvier, 1825 |
| Genera | |
In American English the name gar (or garpike) is strictly applied to members of the Lepisosteidae, a family including seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine, waters of eastern North America, Central America, and the Caribbean islands.[2][3]
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[edit] Etymology
In British English the name gar was originally used for a species of needlefish, Belone belone, found in the North Atlantic, itself likely named after the Old English word gar meaning "spear".[4] Belone belone is now more commonly referred to as the "garpike" or "gar fish" to avoid confusion with the North American gars of the family Lepisosteidae.[5]
The genus name Lepisosteus comes from the Greek lepis meaning "scale" and osteon meaning "bone".[6] Atractosteus is similarly derived from Greek, in this case from atraktos, meaning "arrow".[7]
The fish known as the garfish, freshwater garfish, or sometimes needlefish is a separate species, Xenentodon cancila.
[edit] Distribution
The gars are members of the Lepisosteiformes (or Semionotiformes), an ancient order of "primitive" ray-finned fish; fossils from this order are known from the late Cretaceous onwards. Fossil gars are found in Europe, South America, and North America, indicating that in times past these fish had a wider distribution than they do today. Gars are considered to be a remnant of a group of rather primitive bony fish that flourished in the Mesozoic, and are most closely related to the bowfin, another archaic fish now found only in North America.
[edit] Anatomy and morphology
Gar bodies are elongated, heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long sharp teeth. Their tails are heterocercal, and the dorsal fins are close to the tail.[8] As their vascularised swim bladders can function as lungs,[1] most gar surface periodically to take a gulp of air, doing so more frequently in stagnant or warm water when the concentration of oxygen in the water is low. As a result, they are extremely hardy and able to tolerate conditions that would kill most other fish.
All the gars are relatively big fish, but the alligator gar Atractosteus spatula is the biggest, as specimens having been recorded up to 3 metres (9.8 ft) in length.[9] Even the smaller species, such as Lepisosteus oculatus, are large, commonly reaching lengths of over 60 centimetres (2.0 ft), and sometimes much more.[10]
[edit] Ecology
Gar tend to be slow moving fish except when striking at their prey. They prefer the shallow and weedy areas of rivers, lakes, and bayous often congregating in small groups.[2] They are voracious predators, catching their prey with their needle-like teeth, obtaining with a sideways strike of the head.[10] Gar feed extensively on smaller fish and invertebrates such as crabs.[9] Gar are found across eastern North America from Costa Rica to southern Quebec (for example Lepisosteus osseus).[2] Although gar are primarily found in freshwater habitats several species enter brackish waters and a few, most notably Atractosteus tristoechus, are sometimes found in the sea.[2][11]
[edit] Species
The gar family contains seven species, in two genera:[1]
Family Lepisoteidae
- Genus Atractosteus
- Genus Lepisosteus
[edit] Significance to humans
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Gar flesh is edible, and sometimes available in markets, but unlike the sturgeon that they resemble, their eggs (roe) are poisonous. Several species are traded as aquarium fish.[10]
Gars are of considerable significance to Native American peoples of the southeastern United States where the gar figures prominently in ceremonial life and music.[citation needed]
Alligator Gar have been rumored to attack humans in some rare cases.
To most people they are considered a worthless "trashfish" but to some they are considered a valuable sport fish.
Gars sometimes showup as pets, although there are gars sold as 'false' gars such as the Needlefish family. True Gars are illegal as pets in multiple areas but will occasionaly show up in fish stores.
[edit] References
- ^ a b c "Lepisosteidae". FishBase. Ed. Rainer Froese and Daniel Pauly. January 2009 version. N.p.: FishBase, 2009.
- ^ a b c d "Family Lepisosteidae - Gars". http://filaman.ifm-geomar.de/Summary/FamilySummary.cfm?ID=34. Retrieved 2007-04-21.
- ^ Sterba, G: Freshwater Fishes of the World, p. 609, Vista Books, 1962
- ^ "Gar". http://dictionary.reference.com/browse/gar. Retrieved 2007-04-21.
- ^ "Common Names of Belone belone". http://www.fishbase.org/comnames/CommonNamesList.cfm?ID=47&GenusName=Belone&SpeciesName=belone&StockCode=57. Retrieved 2007-04-21.
- ^ "Genera reference detail". http://filaman.ifm-geomar.de/Eschmeyer/GeneraSummary.cfm?ID=Lepisosteus. Retrieved 2007-04-21.
- ^ "Atractosteus Genera reference detail". http://filaman.ifm-geomar.de/Eschmeyer/GeneraSummary.cfm?ID= Atractosteus. Retrieved 2007-04-21.
- ^ Wiley, Edward G. (1998). Paxton, J.R. & Eschmeyer, W.N.. ed. Encyclopedia of Fishes. San Diego: Academic Press. pp. 78–79. ISBN 0-12-547665-5.
- ^ a b "Atractosteus spatula - Alligator gar". http://www.fishbase.org/summary/SpeciesSummary.php?id=1073. Retrieved 2007-07-19.
- ^ a b c Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN 0-793800-86-2
- ^ Monks N. (editor): Brackish Water Fishes, pp 322-324. TFH 2006, ISBN 0-7938-0564-3
[edit] External links
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