|Order:|| Lepisosteiformes |
O. P. Hay, 1929
|Family:|| Lepisosteidae |
G. Cuvier, 1825
Gars are members of the Lepisosteiformes (or Semionotiformes ), an ancient holosteian order of ray-finned fish; fossils from this order are known from the Late Jurassic onwards. The family Lepisosteidae includes 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 m (6.5 ft) and a weight of over 45 kg (100 lb), and specimens of up to 3 m (9.8 ft) in length have been reported. Unusually, their vascularised swim bladders can function as lungs, and most gars surface periodically to take a gulp of air. Gar flesh is edible and the hard skin and scales of gars are used by humans, but gar eggs are highly toxic.Gars have elongated bodies that are heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long, sharp teeth. Gars are sometimes referred to as "garpike", but are not closely related to pike, which are in the fish family Esocidae. All of the gars are relatively large fish, but the alligator gar (Atractosteus spatula) is the largest – the alligator gar often grows to a length of over
The name gar was originally used for a species of needlefish ( Belone belone ) found in the North Atlantic and likely took its name from the Old English word for "spear".Belone belone is now more commonly referred to as the "garfish" or "gar fish" to avoid confusion with the North American gars of the family Lepisosteidae. Confusingly, the name "garfish" is also commonly used for a number of other species of the related genera Strongylura, Tylosurus and Xenentodon of the family Belonidae.
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.
Fossilized gars have been found in Europe, India, 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 bony fish that flourished in the Mesozoic, and are most closely related to the bowfin. The distribution of the gar Lepisosteidae in North America lies mainly in the shallow, brackish waters off of Texas, Louisiana, and the eastern coast of Mexico, as well as in some of the rivers and lakes that flow to them.A few populations are also present in the Great Lakes region of the United States, living in similar shallow waters.
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.
As their vascularised swim bladders can function as lungs,most gars 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. Experiments on the swim bladder has shown that the temperature of the water affects which respiration method the gar will use: aerial or aquatic. They will increase the aerial breathing rate (breathing air) as temperature of the water is increased. Gars can live completely submerged in oxygenated water without access to air and remain healthy while also being able to survive in deoxygenated water if allowed access to air. This adaptation can be the result of environmental pressures and behavioral factors. As a result of this organ, they are extremely resilient and able to tolerate conditions that most other fish could not survive.
The gar has paired pectoral fins and pelvic fins, as well as an anal fin, a caudal fin, and a dorsal fin.The bone structures within the fins are important to study as they can show homology throughout the fossil record. Specifically, the pelvic girdle resembles that of other actinopterygians while still having some of its own characteristics. Gars have a postcleithrun - which is a bone that is lateral to the scapula, but do not have postpectorals. Proximally to the postcleithrum, the supracleithrum is important as it plays a critical role in opening the gar's jaws. This structure has a unique internal coracoid lamina only present in the Gar species. Near the supracleithrum is the posttemporal bone, which is significantly smaller than other actinopterygians. Gars also have no clavicle bone, although there have been observations of elongated plates within the area.
All the gars are relatively large fish, but the alligator gar Atractosteus spatula is the largest. The largest alligator gar ever caught and officially recorded was 8 ft 5 1⁄4 in (2.572 m) long, weighed 327 lb (148 kg), and was 47 in (120 cm) around the girth. Even the smaller species, such as Lepisosteus oculatus, are large, commonly reaching lengths of over 60 cm (2.0 ft), and sometimes much longer.
Gars 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 in their needle-like teeth with a sideways strike of the head. They feed extensively on smaller fish and invertebrates such as crabs. Gars are found across much of the eastern portion of North America. Although gars are found primarily in freshwater habitats, several species enter brackish waters and a few, most notably Atractosteus tristoechus, are sometimes found in the sea. Some gars travel from lakes and rivers through sewers to get to ponds.
The gar family contains seven extant species, in two genera:
|Cladogram of living gars|
The largest member of the gar family, the alligator gar (Atractosteus spatula ), can measure up to 10 feet long and weigh over 300 pounds.Its body and snout are wide and stocky, and it was named "alligator gar" because locals often mistook it for an alligator. The species can be found in Texas, Oklahoma, the Mississippi River, Ohio, the Missouri river, and the southern drainages into Mexico. Its habitat consists of lakes and bays with slow currents. The gars grow rapidly when young and continue to grow at a slower rate after reaching adulthood. They are deep green or yellow in color. Recreational fishing of the alligator gar became popular due to its massive size and its meat is sold for food. Over five decades of overfishing have brought it close to extinction, and man-made dams have contributed to this loss by restricting the gar's access to the flood plain areas in which it spawns. Some U.S. states have enacted laws to combat overfishing, and reintroduction programs are being carried out in some states, such as Illinois, where human activity has driven the gar to extinction. Before being released, each gar must meet a length requirement to ensure that it has the best chance of survival in the wild. Some states, such as Texas, restrict the number of gar that may be caught in a day, the season in which they may be caught, and the equipment anglers may use to catch them. Some states also impose a minimum length requirement to prevent gar from being caught at too early an age. Scientists have found that the alligator gar can help maintain ecosystem balance by eating invasive species such as the Asian carp, and their success in a particular area can show scientists that area may also make a suitable habitat for other migratory species.
The Florida gar (Lepisosteus platyrhincus ) can be found in the Ocklockonee river, Florida, and Georgia,and prefers muddy or sandy bottoms with bountiful vegetation. It is commonly confused with its cousin, the spotted gar. Uneven black spots cover its head, body, and fins. Green-brown scales run along the back of its body, and the scales on its underbelly are white or yellow. This coloration, which blends well with the gar's surroundings, allows it to ambush its prey. The Florida gar has no ganoid scales on its throat. Female Florida gars grow to lengths between 13 and 34 inches, bigger than their male counterparts.
The spotted gar (Lepisosteus oculatus) is a smaller species of gar,measuring just under four feet long and weighing 15 pounds on average. Like Florida gars, female spotted gars are typically larger than male spotted gars. This gar has dark spots covering its head, body, and fins. Its body is compact, and it has a shorter snout. It prefers to live in clearer shallow water with a depth of 3–5 meters, and to surround itself in foliage. Its habitat is ranges from the waters of Lake Michigan, the Lake Erie Basin, the Mississippi River System, and river drainages along the northern coast of the Gulf of Mexico from the Nueces River in Texas east to the lower Apalachicola River in Florida. It shares its habitat with the alligator gar, its main predator. These smaller gar live an average of 18 years.
The shortnose gar ( Lepisosteus platostomus) is found in the Mississippi River Basin, Indiana, Wisconsin, Montana, Alabama, and Louisiana.It prefers to live in lakes, swamps, and calm pools. The shortnose gar takes its name from its snout, which is shorter and broader than that of other gar species. Like the longnose gar, it has one row of teeth. The upper jaw is longer than the rest of its head. The shortnose gar is deep green or brown in color, similar to the alligator gar. Depending on the clarity of water, spots can be present on the caudal, dorsal, and anal fins. The shortnose gar has a lifespan of 20 years, reaches up to 5 pounds in weight, and grows to lengths of 24-35 inches. It consumes more invertebrates than any other gar, and their stomachs have been found to contain higher Asian carp content than any other native North American fish.
The Longnose gar (Lepisosteus osseus) has a longer, narrower, more cylindrical body,and can be distinguished from other species of gar by its snout, which is more than twice the length of the rest of its head. It can reach up to 6 feet and 8 inches in length and weigh up to 35-80 pounds. Like the shortnose gar, it has only a single row of teeth. Unlike its relatives, it enters brackish water from time to time. Females are larger and live longer than the male longnose gar. Females living 22 years, and males about half as long. There are spots on the head, dorsal, anal, and caudal fins. Depending on the water clarity, the longnose gar comes in two colors. In clear water, they're a dark deep green color. In muddy waters, it's more brown in color. Edges of the ganoid scales and in between are black. These type of gar are occasionally fished by locals, and blamed for eating other fish in the rivers. The longnose gar has a large range of territory in North America, into the Gulf of Mexico. Located in Florida, Quebec, all Great Lakes except Lake Superior, Missouri, Mississippi, Texas, and northern Mexico.
The flesh of gar is edible, but its eggs contain an ichthyotoxin, a type of protein toxin which is highly toxic to humans.The protein can be denatured when brought to a temperature of 120 degrees Celsius, but as the roe's temperature does not typically reach that level when it is cooked, even cooked roe causes severe symptoms. It was once thought that the production of the toxin in gar roe was an evolutionary adaptation to provide protection for the eggs, but bluegills and channel catfish fed gar eggs in experiments remained healthy, even though they are the natural predators of the gar eggs. Crayfish fed the roe were not immune to the toxin, and most died. The roe's toxicities to humans and crayfish may be coincidences, however, and not the result of explicit natural selection.
Several species are traded as aquarium fish.The hard ganoid scales of gars are sometimes used to make jewelry whereas the tough skin is used to make such items as lamp shades. Historically, Native Americans used gar scales as arrowheads, native Caribbeans used the skin for breastplates, and early American pioneers covered the blades of their plows with gar skin. Not much is known about the precise function of the gar in Native American religion and culture other than the ritual "garfish dances" that have been performed by Creek and Chickasaw tribes.
Bowfin are bony fish related to gars in the infraclass Holostei. Common names include mudfish, mud pike, dogfish, griddle, grinnel, swamp trout, and choupique. They are regarded as taxonomic relicts, being the sole surviving species of the order Amiiformes, which dates from the Jurassic to the Eocene, persisting to the present. Although bowfin are highly evolved, they are often referred to as "primitive fish" because they have retained some morphological characteristics of their early ancestors.
A sawshark or saw shark is a member of a shark order (Pristiophoriformes) bearing a unique long, saw-like rostrum edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristiophoriformes, including the longnose or common sawshark, shortnose sawshark, Japanese sawshark, Bahamas sawshark, sixgill sawshark, African dwarf sawshark, Lana's sawshark and the tropical sawshark.
Lepisosteus is a genus of gars in the family Lepisosteidae.
The tropical gar is a species of fish found from southern Mexico to Costa Rica. This gar inhabits a wide range of fresh and brackish water habitats such as rivers, floodplains, lakes and pools, but avoids areas with a strong current. It reaches lengths of up to 1.25 m (4 ft) and a weight up to 2.9 kg (6.4 lb). The tropical gar looks very similar to the longnose gar in color and markings, but can be distinguished by its shorter, broader snout. The tropical gar's diet consists mainly of cichlids and other fish.
The longnose gar, also known as needlenose gar, longnose garpike, and billy gar, is a ray-finned fish in the family Lepisosteidae. The genus may have been present in North America for about 100 million years. There are references to gars being a primitive group of bony fish because they have retained some primitive features, such as a spiral valve intestine, but gars are a highly evolved group of fish, and not primitive in the sense they are not fully developed.
The arapaima, pirarucu, or paiche is any large species of bonytongue in the genus Arapaima native to the Amazon and Essequibo basins of South America. Genus Arapaima is the type genus of the family Arapaimidae. They are among the world's largest freshwater fish, reaching as much as 3 m (9.8 ft). They are an important food fish. They have declined in the native range due to overfishing and habitat loss. In contrast, arapaima have been introduced to several tropical regions outside the native range, where they are sometimes considered invasive species. Its Brazilian Portuguese name, pirarucu, derives from the Tupi language words pira and urucum, meaning "red fish".
The alligator gar is a ray-finned euryhaline fish related to the bowfin in the infraclass Holostei. It is the largest species in the gar family, and among the largest freshwater fishes in North America. The fossil record traces its group's existence back to the Early Cretaceous over 100 million years ago. Gars are often referred to as "primitive fishes", or "living fossils" because they have retained some morphological characteristics of their earliest ancestors, such as a spiral valve intestine, which is also common to the digestive system of sharks, and the ability to breathe both air and water. Their common name was derived from their resemblance to the American alligator, particularly their broad snouts and long, sharp teeth. Anecdotal evidence suggests that an alligator gar can grow up to 10 ft (3.0 m) in length.
Needlefish or long toms are piscivorous fishes primarily associated with very shallow marine habitats or the surface of the open sea. Some genera include species found in marine, brackish, and freshwater environments, while a few genera are confined to freshwater rivers and streams, including Belonion, Potamorrhaphis, and Xenentodon. Needlefish closely resemble North American freshwater gars in being elongated and having long, narrow jaws filled with sharp teeth, and some species of needlefishes are referred to as gars or garfish despite being only distantly related to the true gars. In fact, the name "garfish" was originally used for the needlefish Belone belone in Europe and only later applied to the North American fishes by European settlers during the 18th century.
Bowfishing is a method of fishing that uses specialized archery equipment to shoot and retrieve fish. Fish are shot with a barbed arrow that is attached with special line to a reel mounted on the bow. Some freshwater species commonly hunted include common carp, grass carp, bighead carp, alligator gar, and bowfin. In saltwater, rays and sharks are regularly pursued.
Pejelagarto is the Spanish name for the large freshwater gar very common in the Mexican Southeast and particularly in the state of Tabasco. They are notable for their primitive appearance, and the family to which they belong, the Lepisosteidae, appeared during the Cretaceous and have survived to the present day relatively unmodified.
The Florida gar is a species of gar found in the US from the Savannah River and Ochlockonee River watersheds of Georgia and throughout peninsular Florida. Florida gar can reach a length over 3 ft (91 cm). The young feed on zooplankton and insect larvae, as well as small fish. Adults mainly eat fish, shrimp, and crayfish. Although edible, they are not popular as food. The roe is highly toxic to many animals, including humans and birds. Gar are mentioned in the John Anderson song "Seminole Wind".
The spotted gar is a freshwater fish native to North America that has an abundance of dark spots on its head, fins, and dart-like body. Spotted gar have an elongated mouth with many needle-like teeth to catch other fish and crustaceans. It is one of the smallest of the seven species of gar found in North America, growing 2–3 ft in length and weighing 4-6 lb (1.8–2.7 kg) typically. Gars have diamond-shaped, thick, enamel (ganoid) scales. The name Lepisosteus is Greek for "bony scale".
The shortnose gar is a primitive freshwater fish of the family Lepisosteidae. It is native to the United States where its range includes the Mississippi and Missouri River basins, ranging from Montana to the west and the Ohio River to the east, southwards to the Gulf Coast. It inhabits calm waters in large rivers and their backwaters, as well as oxbow lakes and large pools. It is a long, slender fish, brown or olive green above and whitish below. It typically grows to about 60 cm (24 in) and is armored by rows of interlocking, rhomboidal ganoid scales.
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term scale derives from the Old French "escale", meaning a shell pod or husk.
Kyphosichthys is an extinct genus of basal actinopterygian bony fish known from the lower Middle Triassic (Anisian) marine deposits in Luoping, eastern Yunnan Province, southwestern China. The species is the first known fossil record of highly deep-bodied Neopterygii ginglymodians.
The Cuban gar is a fish in the family Lepisosteidae. It is a tropical, freshwater species, although it also inhabits brackish water. It is found in rivers and lakes of western Cuba and the Isla de la Juventud. The flesh of the fish is edible, but the eggs are poisonous for humans.