gar

gar, member of the family Lepisosteidae, freshwater fishes found in the warmer rivers and lakes of the S United States, Central America, Mexico, and the West Indies. Gars are highly predacious and destroy many useful fish. They are cylindrical fishes with long jaws and formidable teeth; their peculiar armature of diamond-shaped platelike scales, composed of a hard inorganic salt, is often found also in fossil fish. The largest species is the 9-ft (275-cm) alligator gar of the Mississippi valley. Others are the long-nosed gar (Lepisosteus osseus), the spotted gar, and the short-nosed gar. The name garfish is sometimes used for the gar but is more correctly applied to the saltwater gar (see needlefish). Gars are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Lepisosteiformes, family Lepisosteidae.

Any of several large North or Central American fishes of the genus Lepisosteus. They are related to the bowfin and date back to the Eocene Epoch. Gars are confined chiefly to fresh water, though some species enter brackish or salt water. They frequently bask at the surface in sluggish waters and commonly breathe atmospheric air. Their jaws and face form a sharp-toothed beak, and their body is encased in an armour of diamond-shaped, thick scales. Their eggs are toxic to predators. They are highly voracious predators, with long rows of needlelike teeth. The alligator gar of the southern U.S. reaches a length of about 10 ft (3 m) and is one of the largest freshwater fishes.

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In American English the name gar (or garpike) is strictly applied to members of the Lepisosteus, 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.

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". 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.

The genus name Lepisosteus comes from the Greek lepis meaning "scale" and osteon meaning "bone". Atractosteus is similarly derived from Greek, in this case from atraktos, meaning "arrow".

Distribution

The gars are members of the Lepisosteiformes (or Semionotiformes), an ancient order of "primitive" ray-finned fish; fossil gars are known from the Permian onwards. Their primitive traits are their very hard armour-like ganoid scales, a swimming bladder open to the pharynx that can function as a lung and the heterocercal tail. Fossil gars are found in both Europe 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.

Anatomy and morphology

Gar bodies are elongated, heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long sharp teeth. Tails are heterocercal, and the dorsal fins are close to the tail. As their vascularised swim bladders can function as lungs, 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 champion, as specimens having been recorded up to 3 meters in length. Even the smaller species, such as Lepisosteus oculatus, are large, commonly reaching lengths of over 60 cm (2 feet), and sometimes much more.

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. They are voracious predators, catching their prey with their needle-like teeth, obtaining with a sideways strike of the head. Gar feed extensively on smaller fish and invertebrates such as crabs. Gar are found across eastern North America from Costa Rica to southern Quebec (for example Lepisosteus osseus). 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.

Significance to humans

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.

Cultural Significance

The Gar fish is of considerable significance to Native American peoples of the southeastern United States where the gar figures prominently in ceremonial life and music. See Creek, Seminole

References

External links

• Family Lepisosteidae entry at FishBase