Gar

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Gar
Temporal range: Kimmeridgian–Recent [1]
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Lepisosteus oculatus.jpg
Spotted gar
(Lepisosteus oculatus)
Scientific classification
Kingdom:
Phylum:
Class:
Subclass:
Infraclass:
Order:
O. P. Hay, 1929
Family:
G. Cuvier, 1825
Genera

Gars (or garpike) 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] [3] Gars have elongated bodies that are heavily armored with ganoid scales, [4] and fronted by similarly elongated jaws filled with long, sharp teeth. All of the gars are relatively large fish, but the alligator gar (Atractosteus spatula) is the largest, as specimens have been reported to be 3 m (9.8 ft) in length; [5] however, they typically grow to 2 m (6.5 ft) and weigh over 45 kg (100 lb). [6] Unusually, their vascularised swim bladders can function as lungs, [7] 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; however their eggs are highly toxic.

Semionotiformes order of fishes (fossil)

Semionotiformes is an order of primitive, ray-finned, primarily freshwater fish from the Triassic to the Cretaceous. The best-known genus is Semionotus of Europe and North America.

Holostei infraclass of fishes

Holostei are bony fish. There are eight species divided among two orders, the Amiiformes represented by a single living species, the Bowfin, and the Lepisosteiformes, represented by seven living species in two genera, the gars. Further species are to be found in the fossil record and the group is often regarded as paraphyletic. Holosteians are closer to teleosts than are the chondrosteans, the other group intermediate between teleosts and cartilaginous fish. The spiracles are reduced to vestigial remnants and the bones are lightly ossified. The thick ganoid scales of the gars are more primitive than those of the bowfin.

The Late Jurassic is the third epoch of the Jurassic period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.

Contents

Etymology

The name gar was originally used for a species of needlefish ( Belone belone ) found in the North Atlantic and likely taking its name from the Old English word for "spear". [8] 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. [9] Confusingly, the name "garfish" is commonly used for a number of other species of the related genera Strongylura, Tylosurus and Xenentodon of the family Belonidae.

Needlefish family of fish (Belonidae)

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.

Old English, or Anglo-Saxon, is the earliest historical form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers probably in the mid-5th century, and the first Old English literary works date from the mid-7th century. After the Norman conquest of 1066, English was replaced, for a time, as the language of the upper classes by Anglo-Norman, a relative of French. This is regarded as marking the end of the Old English era, as during this period the English language was heavily influenced by Anglo-Norman, developing into a phase known now as Middle English.

<i>Strongylura</i> genus of fishes

Strongylura is a genus of needlefishes.

The genus name Lepisosteus comes from the Greek lepis meaning "scale" and osteon meaning "bone". [10] Atractosteus is similarly derived from Greek, in this case from atraktos, meaning arrow. [11]

Greek language language spoken in Greece, Cyprus and Southern Albania

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

Distribution

Fossil gars are 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 and Louisiana, and off the eastern coast of Mexico. [12] [13] A few populations are also present in the Great Lakes region of the United States, living in similar shallow waters. [14]

Osteichthyes superclass of fishes

Osteichthyes, popularly referred to as the bony fish, is a diverse taxonomic group of fish that have skeletons primarily composed of bone tissue, as opposed to cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 420 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes.

The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. It is also called the Age of Reptiles and the Age of Conifers.

Bowfin species of fish

Bowfin are bony fishes 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 fishes" because they have retained some morphological characteristics of their early ancestors.

Anatomy

Large gar in an aquarium Gar shedd.jpg
Large gar in an aquarium

Scales

Atractosteus fossil Atractosteus.JPG
Atractosteus fossil

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. [15]

Jaw opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food; structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of most animals

The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of most animals.

Dorsal fin The fin on the dorsal.

A dorsal fin is a fin located on the back of most marine and freshwater vertebrates such as fishes, cetaceans, and the (extinct) ichthyosaur. Most species have only one dorsal fin, but some have two or three.

Swim bladder

As their vascularised swim bladders can function as lungs, [7] 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. [16] This adaptation can be the result of environmental pressures and behavioral factors. [17] As a result of this organ, they are extremely resilient and able to tolerate conditions that most other fish could not survive in.

Swim bladder gas-filled organ that contributes to the ability of a fish to control its buoyancy

The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish to control their buoyancy, and thus to stay at their current water depth without having to waste energy in swimming. Also, the dorsal position of the swim bladder means the center of mass is below the center of volume, allowing it to act as a stabilizing agent. Additionally, the swim bladder functions as a resonating chamber, to produce or receive sound.

Pectoral girdle

Medial and lateral view of Lepisosteidae pectoral girdle Lepisosteidae Pectoral Girdle.jpg
Medial and lateral view of Lepisosteidae pectoral girdle

The gar has paired appendages, including pectoral fins, pelvic fins, while also having an anal fin, caudal fin, and a dorsal fin. [18] 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 yet 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. Proximal to 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. [19]

Morphology

Fin chart for shortnose gar Lepisosteus platostomus - fins.jpg
Fin chart for shortnose gar

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 14 in (2.572 m) long, weighed 327 lb (148 kg), and was 47 in (120 cm) around the girth. [20] Even the smaller species, such as Lepisosteus oculatus, are large, commonly reaching lengths of over 60 cm (2.0 ft), and sometimes much more. [21]

Ecology

A range map of Lepisosteiformes. Opacity map of Lepisosteiformes.svg
A range map of Lepisosteiformes.

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. [2] They are voracious predators, catching their prey with their needle-like teeth, obtained with a sideways strike of the head. [21] They feed extensively on smaller fish and invertebrates such as crabs. [5] Gars are found across much of North America (for example Lepisosteus osseus). [2] Although gars are primarily found 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. [2] [22]

Species

The gar family contains seven extant species, in two genera: [7]

Cladogram of living gars [23]
Lepisosteidae
Atractosteus

A. tropicus

A. tristoechus

A. spatula

Lepisosteus

L. oculatus

L. platyrhincus

L. osseus

L. platostomus

Family Lepisosteidae

Roe

Lepisosteus platyrhincus Kaimanfische (Lepisosteus).jpg
Lepisosteus platyrhincus

Gar flesh is edible, and sometimes available in markets, but unlike the sturgeon they resemble, their eggs are highly toxic to humans. [25] Gar eggs are toxic because of a protein toxin called ichthyotoxin. [26] The protein can be denatured when brought to a temperature of 120 degrees celsius. [27] When cooking roe, the temperature does not typically get that high so the protein stays intact and 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. However, bluegills and channel catfish were fed gar eggs and remained healthy, even though they are the natural predators of the gar eggs. Crayfish were not immune to the toxin and most of the crayfish that ate the roe died. The immunity to the ichthyotoxins in bluegills and catfish suggests that the toxin came about for a reason other than keeping the gar eggs safe. It may just be a coincidence that the roe is toxic to humans and crayfish. [26]

Significance to humans

Several species are traded as aquarium fish. [21] The hard skin and scales of the gar were used by humans. Native Americans used the scales of the gar as arrowheads, native Caribbeans used the skin for breastplates, and early American pioneers covered the blades of their plows in gar skin. [28] Not much is known about the precise function of the gar in Native American religion and culture, but besides using the gar, Creek and Chickasaw people have ritual "garfish dances". [29]

A gar leaps out of the water. Gar jumping out of water to eat horsefly.jpg
A gar leaps out of the water.

Related Research Articles

The halfbeaks, also called spipe fish or spipefish are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar viviparous halfbeaks have often been included in this family.

Lepisosteus is a genus of gars in the family Lepisosteidae.

Combtooth blenny Family of fishes

Combtooth blennies are blenniiformids; percomorph marine fish of the family Blenniidae, part of the order Blenniiformes. They are the largest family of blennies with around 400 known species. Combtooth blennies are found in tropical and subtropical waters in the Atlantic, Pacific and Indian Oceans; some species are also found in brackish and even freshwater environments.

Longnose gar species of fish

The longnose gar is a primitive ray-finned fish of the gar family. It is also known as the needlenose gar. L. osseus is found along the east coast of North and Central America in freshwater lakes and as far west as Kansas and Texas and southern New Mexico. The gar have been present in North America for about 100 million years.

Alligator gar species of 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 existence back to the Early Cretaceous over a hundred 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.

Garfish species of edible fish, in the genus Belone

The garfish, or sea needle, is a pelagic, oceanodromous needlefish found in brackish and marine waters of the Atlantic Ocean and the Mediterranean, Caribbean, Black, and Baltic Seas.

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 New Zealand piper is a halfbeak found all around New Zealand in shallow inshore waters.

<i>Xenentodon cancila</i> species of fish

Xenentodon cancila, the freshwater garfish, is a species of needlefish found in freshwater and brackish habitats in South and Southeast Asia.

Florida gar species of fish

The Florida gar is a species of gar found in the USA from the Savannah River and Ochlockonee River watersheds of Georgia and throughout peninsular Florida. Florida gars can reach a length of 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".

Spotted gar Spotted gar

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 pounds on average. Gars have diamond-shaped, thick, enamel (ganoid) scales. The name Lepisosteus is Greek for "bony scale."

Crocodilefish may refer to:

Shortnose gar species of fish

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 armoured by rows of interlocking, rhomboidal ganoid scales.

Ichthyotoxins are compounds which are either toxic to fish or are toxins produced by fish. The toxins can be found in gar eggs and the eggs of several other species' roe. It can also be found in some species of algae such as prymnesium parvum. They include euglenophycin and prymnesins, made by algae and can cause large-scale fish deaths, and ostracitoxin made by boxfish. Many toxin producing algal species can be found both in marine and fresh water environments when the algae is in bloom. The toxin is protein based and is poisonous to humans, small mammals, and some fish. An ichthyotoxic poisoning can cause symptoms ranging in severity dependent on how much toxin was consumed. The symptoms of an ichthyotoxin poisoning can include headache, vomiting, diarrhea, dizziness, drop in blood pressure, and many others.

Cuban gar species of fish

The Cuban gar is a fish in the family Lepisosteidae. It is a tropical fresh water 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.

The short-beaked garfish is an uncommon species of needlefish in marine waters of the eastern Atlantic Ocean. This pelagic needlefish is present off the coasts of Ireland, Spain, Portugal, and the United Kingdom, and possibly in the Mediterranean Sea, as well. This species was thought to be the same as the garfish because they share the same waters. Belone svetovidovi matures at 30 cm (12 in) and can grow to a maximum of 65 cm (26 in) while Belone belone can be 95 cm (38 in). Like all needlefish, this one has an elongated body with beak-like jaws that are lined with razor sharp teeth. The Short-beaked garfishs' lower jaw is longer than the upper. Its body is silvery like most needlefish and has a black stripe running across its lateral line. The dorsal and anal fins are very close to the caudal peduncle. These fish are Oviparous. Eggs may be found attached to objects in the water by tendrils on the egg's surface. These spherical eggs are dispersed on the sea floor (demersal). Not much is known about this fish's feeding habits. It likely preys on small oceangoing fish. It has been caught using mackerel. Needlefish tend to be surface fish, so are preyed upon like Atlantic mackerel, European pilchard, sand smelt, etc.

Uranoscopus brunneus, the dark-finned stargazer, is a newly discovered member of the group Uranoscopidae, the benthic living fishes distributed worldwide in tropical and temperate oceans.

References

  1. 1 2 Paulo M. Brito; Jésus Alvarado-Ortega; François J. Meunier (2017). "Earliest known lepisosteoid extends the range of anatomically modern gars to the Late Jurassic". Scientific Reports. 7: Article number 17830. doi:10.1038/s41598-017-17984-w.
  2. 1 2 3 4 "Family Lepisosteidae - Gars" . Retrieved 2007-04-21.
  3. Sterba, G: Freshwater Fishes of the World, p. 609, Vista Books, 1962
  4. Sherman, Vincent R.; Yaraghi, Nicholas A.; Kisailus, David; Meyers, Marc A. (2016-12-01). "Microstructural and geometric influences in the protective scales of Atractosteus spatula". Journal of the Royal Society Interface. 13 (125): 20160595. doi:10.1098/rsif.2016.0595. ISSN   1742-5689. PMC   5221522 . PMID   27974575.
  5. 1 2 "Atractosteus spatula - Alligator gar" . Retrieved 2007-07-19.
  6. "Atractosteus spatula". Florida Museum of Natural History. Retrieved 2016-04-21.
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  10. "Genera reference detail" . Retrieved 2007-04-21.
  11. "Genera reference detail" . Retrieved 2016-02-21.
  12. "Atractosteus spatula :: Florida Museum of Natural History". www.floridamuseum.ufl.edu. Retrieved 2018-05-11.
  13. "Lepisosteus oculatus (Spotted gar)". Animal Diversity Web. Retrieved 2018-05-11.
  14. "Spotted Gar (Lepisosteus oculatus) - Species Profile". nas.er.usgs.gov. Retrieved 2018-05-11.
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  17. Hill, Loren (1972). "Social Aspects of Aerial Respiration of Young Gars (Lepisosteus)". The Southwestern Naturalist. 16 (3): 239–247. JSTOR   3670060.
  18. Becker, George (1983). "Fishes of Wisconsin" (PDF): 239–248.
  19. Malcolm, Jollie. "Development of Cranial and Pectoral Girdle Bones of Lepisosteus with a Note on Scales". Copeia. American Society of Ichthyologists and Herpetologists (ASIH). JSTOR   1445204.
  20. "Alligator Gar (Atractosteus spatula)". Texas Parks & Wildlife Department. Retrieved March 8, 2016.
  21. 1 2 3 Kodera H. et al.: Jurassic Fishes. TFH, 1994, ISBN   0-7938-0086-2 [ page needed ]
  22. Monks N. (editor): Brackish Water Fishes, pp 322–324. TFH 2006, ISBN   0-7938-0564-3
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  24. Cavin, Lionel; Martin, Michel; Valentin, Xavier (1996). "Occurrence of Atractosteus africanus (actinopterygii, lepisosteidae) in the early Campanien of Ventabren (Bouches-du-Rhône, France). Paleobiogeographical implications". Revue de Paléobiologie. 15 (1): 1–7.
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  27. Fuhrman, Frederick A.; Fuhrman, Geraldine J.; Dull, David L.; Mosher, Harry S. (1969-05-01). "Toxins from eggs of fishes and amphibia". Journal of Agricultural and Food Chemistry. 17 (3): 417–424. doi:10.1021/jf60163a043. ISSN   0021-8561.
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  29. Spitzer, Mark (2010). Season of the Gar: Adventures in Pursuit of America's Most Misunderstood Fish. U of Arkansas P. pp. 118–19. ISBN   978-1-55728-929-2.