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113-526: The bowfin ( Amia calva ) is a bony fish, native to North America. Common names include mudfish , mud pike , dogfish , grindle , grinnel , swamp trout , and choupique . It is regarded as a relict , being one of only two surviving species of the Halecomorphi , a group of fish that first appeared during the Early Triassic , around 250 million years ago. The bowfin is often considered

226-572: A feeding tube is utilized, and sometimes a tracheotomy is also performed to maintain respiration in case of swollen muscles. In a technique illustrated in the 19th century, the flesh of the face is incised along the inferior of the mandible and peeled upward for the bone's removal. Complications can involve difficulties with free flap transfer and airway management. Additional side effects include pain, infection, numbness, and (rarely, fatal) bleeding. Even successful surgeries can result in deformity , with an extreme version being referred to as

339-471: A predatory fish native to streams and lakes of North America and Eurasia, is also commonly mistaken for bowfin. Burbots can be distinguished by their flat head and chin barbel, long anal fin, and pelvic fins situated beneath the pectoral fins. The first fish lacked jaws and used negative pressure to suck their food in through their mouths. The jaw in the bowfin is a result of their evolutionary need to be able to catch and eat bigger and more nutritious prey. As

452-402: A " living fossil " because they have retained some morphological characteristics of their early ancestors . It is one of two species in the genus Amia, along with Amia ocellicauda , the eyespot bowfin. The closest living relatives of bowfins are gars , with the two groups being united in the clade Holostei . Bowfins are demersal freshwater piscivores , commonly found throughout much of

565-455: A 'twin fracture' on the opposite side. There is no universally accepted treatment protocol, as there is no consensus on the choice of techniques in a particular anatomical shape of mandibular fracture clinic. A common treatment involves attachment of metal plates to the fracture to assist in healing. The mandible may be dislocated anteriorly (to the front) and inferiorly (downwards) but very rarely posteriorly (backwards). The articular disk of

678-604: A better model to study vertebrate genome organization than common teleost model organisms such as zebrafish . Bowfin are stalking, ambush predators that customarily move into the shallows at night to prey on fish, amphibians, and aquatic invertebrates such as crawfish, other crustaceans, mollusks, and aquatic insects. Young bowfin feed mostly on small crustaceans , while adults are mostly piscivorous , but also known to be opportunistic. Some common examples of prey include frogs, bass, other bowfin, dragonflies, sunfish, crawfish, etc. Bowfin are remarkably agile, can move quickly through

791-402: A bone (ossifies) from Meckel's cartilage, which forms the cartilaginous bar of the mandibular arch and, dorsally, parts of the middle ear. The two sides of the jawbone are inferiorly fused at the mandibular symphysis (the chin) during the first year of life. The cartilage of the ramus is replaced by fibrous tissue, which persists to form the sphenomandibular ligament . Between the lingula and

904-421: A bowfin aestivating (in a dormant state) in a chamber 4 inches (10 cm) below the ground surface, 8 inches (20 cm) in diameter, .25 miles (0.4 km) from a river. It was further noted that flood levels had previously reached the area, and receded. It is not unusual for riverine species like bowfin to move into backwaters with flood currents, and become trapped when water levels recede. While aestivation

1017-525: A condition of shock in humans, e.g. when someone's mouth suddenly hangs agape in response to something. The exaggerated visual gag of a jaw dropping to the floor was a trademark of American animation director Tex Avery , who would often employ it when the Big Bad Wolf spies a sexually attractive woman. Gobstoppers , a type of hard candy, are known in North America as jawbreakers due to

1130-473: A deceased person's age. Dental remains of Nazi leader Adolf Hitler , including part of a mandible with teeth, were the solitary physical evidence used to confirm his death in 1945. In the Hebrew Bible and Christian Old Testament Book of Judges , Samson used a donkey's jawbone to kill a thousand Philistines . As early as 1900, the phrase jaw-dropping was used as an adjective to describe

1243-401: A faint ridge, the oblique line, which is continuous with the anterior border of the ramus. Attached to this is the masseter muscle ( related to mastication ), the depressor labii inferioris and depressor anguli oris (which support the mouth ), and the platysma (extending down over much of the neck ). From the inside, the mandible appears concave. On either side of the lower symphysis

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1356-598: A group that includes many extinct species in several families. Halecomorphs were generally accepted as the sister group to Teleostei but not without question. While a halecostome pattern of neopterygian clades was produced in morphology-based analyses of extant actinopterygians , a different result was produced with fossil taxa which showed a monophyletic Holostei. Monophyletic Holostei were also recovered by at least two nuclear gene analyses, in an independent study of fossil and extant fish, and in an analysis of ultraconserved genomic elements. The extant ray-finned fish of

1469-451: A jaw full of sharp teeth which requires careful handling. The current tackle record is 21.5 lb (9.8 kg) Bowfin were once considered to have little commercial value because of its poor-tasting meat which has been referred to as "soft, bland-tasting and of poor texture". However, it is considered quite palatable if cleaned properly and smoked , or prepared fried, blackened , used in courtbouillion , or in fishballs or fishcakes. Over

1582-458: A lack of central chemoreceptor regulation. Instead, bowfin respiratory patterns respond to water oxygen content and water temperature, as water temperatures play a role in oxygen content. In the lab, bowfin showed an increase in the breathing rate when the temperatures were raised above 10°C. Bowfin also showed an increase in breathing rate when exposed to lower oxygen levels in the water. Herpetologist W. T. Neill reported in 1950 that he unearthed

1695-561: A more common and widespread ancestor. Known to science only since 1968, it seems to have disappeared. Studies have been done on relict populations in isolated mountain and valley habitats in western North America, where the basin and range topography creates areas that are insular in nature, such as forested mountains surrounded by inhospitable desert, called sky islands . Such situations can serve as refuges for certain Pleistocene relicts, such as Townsend's pocket gopher , while at

1808-418: A notochord. The bowfin has a rounded heterocercal tail that resembles a homocercal tail. This type of tail gives the body a streamlined shape which allows the bowfin to improve its swimming ability by reducing drag. These types of tails are common in fish with gas bladders, because the bladder supplies the fish with natural buoyancy. The bowfin is a member of actinopterygii which means that the pectoral girdle

1921-472: A relict species has already contracted to the degree that it is narrowly endemic . For this reason, the traditional conservation tool of translocation has recently been reframed as assisted migration of narrowly endemic, critically endangered species that are already (or soon expected) to experience climate change beyond their levels of tolerance. Two examples of critically endangered relict species for which assisted migration projects are already underway are

2034-426: A result of being able to gather more nutrients, Bowfin are able to live a more active lifestyle. The jaw of a bowfin has several adaptations. The maxilla and premaxilla are fused and the posterior chondrocranium articulates with the vertebra which allows the jaw freedom to rotate. The suspensorium includes several bones and articulates with the snout, brain case, and the mandible. When the jaw opens epaxial muscles lift

2147-431: A separate ossific center ( splenial center ), is formed in the human mandible by an ingrowth from the main mass of the bone. At birth, the body of the bone is a mere shell, containing the sockets of the two incisor, the canine, and the two deciduous molar teeth , imperfectly partitioned off from one another. The mandibular canal is of large size and runs near the lower border of the bone; the mental foramen opens beneath

2260-491: A shorter anal fin, a more rounded head, pelvic fins at a greater distance from the pectoral fins than in the northern snakehead and the presence of the gular plate on the ventral side of the lower jaw. Another noticeable difference is that bowfin scales do not continue uniformly from their body to their head. Bowfin heads are smooth and free of scales, whereas the northern snakehead has scales that uniformly continue from their body through to their head. The burbot ( Lota lota ),

2373-690: A single living species in Australia. Another relict from the Triassic is Pholadomya , a common clam genus during the Mesozoic, now confined to a single rare species in the Caribbean. The tuatara endemic to New Zealand is the only living member of the once-diverse reptile order Rhynchocephalia , which has a fossil record stretching back 240 million years and during the Mesozoic era was globally distributed and ecologically diverse. An example from

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2486-630: A time when the islands were connected to the mainland, and these species were once conspecific with a more widespread species, now the cinereus shrew , the three populations having diverged through speciation . In botany , an example of an ice age relict plant population is the Snowdon lily , notable as being precariously rare in Wales . The Welsh population is confined to the north-facing slopes of Snowdonia , where climatic conditions are apparently similar to ice age Europe. Some have expressed concern that

2599-409: A tunnel-like entrance at one side. The diameter of the nests commonly range between 39–91 cm (15–36 in), at a water depth of 61–92 cm (24–36 in). During spawning season, the fins and underside of male bowfin often change in color to a bright lime green. The courtship/spawning sequence lasts one to three hours, and can repeat up to five times. Courtship begins when a female approaches

2712-420: Is a taxon that persists as a remnant of what was once a diverse and widespread population. Relictualism occurs when a widespread habitat or range changes and a small area becomes cut off from the whole. A subset of the population is then confined to the available hospitable area, and survives there while the broader population either shrinks or evolves divergently . This phenomenon differs from endemism in that

2825-448: Is absorbed so that the mandibular canal becomes nearer the superior border. Sometimes with excessive alveolar process absorption, the mandibular canal disappears entirely and deprives the IAN of its bony protection, although soft tissue continues to guard the nerve. The surgical removal ( resection ) of all or part of the jawbone is known as a mandibulectomy . The removal of a small portion

2938-429: Is anecdotally documented by multiple researchers, laboratory experiments have suggested instead that bowfin are physiologically incapable of surviving more than three to five days of air exposure. However, no field manipulation has been performed. Regardless of the lack of evidence confirming the bowfin's ability to aestivate, it has been noted that bowfin can survive prolonged conditions of exposure to air because they have

3051-399: Is below the oblique line. The mandibular canal, with the mental foramen opening from it, is closer to the alveolar border. The ramus is oblique in direction, the angle measures about 140°, and the neck of the condyle is more or less bent backward. The posterior of the mandible is notoriously resistant to the full effects of local anesthesia . The IAN provides sensory innervation to much of

3164-443: Is between 12–26 °C (54–79 °F), with 18 °C (64 °F) the temperature of maximum activity. Air breathing is at a maximum in the range 18.4–29.6 °C (65.1–85.3 °F). Bowfin do not use central chemoreceptor regulation for respiration control. Experiments manipulating the oxygen content, carbon dioxide content, and pH of bowfin extradural fluid did not affect breathing rate, heart rate, or blood pressure pointing to

3277-479: Is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula of the mandible , which gives attachment to the sphenomandibular ligament ; at its lower and back part is a notch from which the mylohyoid groove runs obliquely downward and forward, and lodges the mylohyoid vessels and nerve. Behind this groove is a rough surface, for the insertion of the medial pterygoid muscle . The mandibular canal runs obliquely downward and forward in

3390-459: Is known as partial mandibulectomy and a larger portion segmental mandibulectomy . This can be performed to remove a tumor, circumvent cancer in nearby areas, and/or in response to infection, osteonecrosis , or injury. The removed portion can be replaced with metal plating or bone from elsewhere in the body. Oral muscles tend to work differently after the procedure, requiring therapy to relearn operations such as eating and speaking. During recovery,

3503-430: Is long-lived, with age up to 33 years reported. The typical length of a bowfin is 50 cm (20 in); females typically grow to 65–70 cm (26–28 in), males to 50–65 cm (20–26 in). They can reach 109 cm (43 in) in length, and weigh 9.75 kg (21.5 lb). Young of the year typically grow to 13–23 cm (5.1–9.1 in) by October. Females tend to grow larger than males. The body of

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3616-440: Is more pronounced in males but can be visualized and palpated in females. Rarely, a bifid IAN may be present, resulting in a second and more inferiorly placed mandibular foramen. This can be detected by noting a doubled mandibular canal via radiograph. The mandible forms the lower jaw and holds the lower teeth in place. It articulates with the left and right temporal bones at the temporomandibular joints. The condyloid process,

3729-434: Is partly endochondral but mostly dermal bone . In this group of fish the fins function to maneuver, brake, and for slight positional adjustments. The pectoral girdle of the bowfin has six parts. The post temporal, supracleithrum, postcleithrum, cleithrum, scapulacoracoid, and the clavicle make up the pectoral girdle . The pectoral girdle is attached to the skull. The paired pectoral and pelvic fins of fish are homologous with

3842-446: Is referred to as the dentary bone or os dentale , and forms the body of the outer surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a prearticular bone, while the articular bone forms the articulation with the skull proper. A set of three narrow coronoid bones lie above

3955-616: Is restricted to freshwater environments in North America, including much of the eastern United States and adjacent southern Canada from the St. Lawrence River and Lake Champlain drainage of southern Ontario and Quebec westward around the Great Lakes in southern Ontario into Minnesota. Historically, their distribution in North America included the drainage basins of the Mississippi River from Quebec to northern Minnesota,

4068-426: Is so named for its long, undulating dorsal fin consisting of 145 to 250 rays that runs from the middle of the back to the base of the tail. The skull of the bowfin is made of two layers of skull, the dermatocranium and the chondrocranium . The chondrocranium layer cannot be seen because it is located below the dermal bones. The bowfin skull is made up of 28 fused bones, which compose the dermatocranium. The roof of

4181-448: Is the mental spine (which can be faint or fused into one), to which the genioglossus (the inferior muscle of the tongue ) attaches; the geniohyoid muscle attaches to the lower mental spine. Above the mental spine, a median foramen and furrow can line the symphysis. Below the mental spine is an oval depression (the digastric fossa of the mandible ) where the digastric muscle attaches. Extending backward and upward on either side from

4294-533: Is the thylacine of Tasmania, a relict marsupial carnivore that survived into modern times on an island, whereas the rest of its species on mainland Australia had gone extinct between 3000 and 2000 years ago. Another example is Omma , a genus of beetle with a fossil record extending back over 200 million years to the Late Triassic and found worldwide during the Jurassic and Cretaceous, now confined to

4407-426: Is useful in understanding the ecology and conservation status of populations that have become insularized, meaning confined to one small area or multiple small areas with no chance of movement between populations. Insularization makes a population vulnerable to forces that can lead to extinction , such as disease, inbreeding , habitat destruction , competition from introduced species , and global warming . Consider

4520-571: The Andy Gump deformity after the comic book character , whose design apparently lacks a jaw; proposed reconstruction methods include implanting synthetic material , potentially involving 3D printing . Bone loss (as in osteoporosis ) can be mitigated in the jawbone via bone grafting , which is sometimes performed to support dental implants (replacing teeth individually or in groups ). Mandibular prosthetics date back to ancient Egypt and China , but significant advancements were made in

4633-488: The Eastern Seaboard or Gulf of Mexico . Their preferred habitat includes vegetated sloughs, lowland rivers and lakes, swamps, and backwater areas; they are also occasionally found in brackish water. They are stalking, ambush predators known to move into the shallows at night to prey on fish and aquatic invertebrates such as crawfish, mollusks, and aquatic insects. Like gars, bowfin are bimodal breathers—they have

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4746-477: The Neolithic advent of agriculture ( c.  10,000 BCE ), human jaws evolved to be smaller . Although it is the strongest bone of the facial skeleton , the mandible tends to deform in old age; it is also subject to fracturing . Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally, the bone is of great forensic significance. In humans ,

4859-720: The Pliocene other than G. biloba . The Saimaa ringed seal ( Phoca hispida saimensis ) is an endemic subspecies, a relict of last ice age that lives only in Finland in the landlocked and fragmented Saimaa freshwater lake complex. Now the population has less than 400 individuals, which poses a threat to its survival. Another example is the relict leopard frog once found throughout Nevada , Arizona , Utah , and Colorado , but now only found at Lake Mead National Recreation Area in Nevada and Arizona. The concept of relictualism

4972-401: The bichir and to most other vertebrates . This is in contrast, however, with teleost fish, which have a fragmented ParaHox cluster, probably because of a whole genome duplication event in their lineage. The presence of an intact ParaHox gene cluster suggests that bowfin ancestors separated from other fish before the last common ancestor of all teleosts appeared. Bowfin are thus possibly

5085-592: The climate changed and woodlands were replaced by savanna . They persisted in Europe in the last remaining forests as a relict of the Oligocene: a relict species in a relict habitat. An example of divergent evolution creating relicts is found in the shrews of the islands off the coast of Alaska, namely the Pribilof Island shrew and the St. Lawrence Island shrew . These species are apparently relicts of

5198-434: The fossil record, and yet is still living, such an organism is sometimes referred to as a living fossil . However, a relict need not be currently living. An evolutionary relict is any organism that was characteristic of the flora or fauna of one age and that persisted into a later age, with the later age being characterized by newly evolved flora or fauna significantly different from those that came before. A notable example

5311-409: The maxilla ). The jawbone is the skull 's only movable, posable bone, sharing joints with the cranium's temporal bones . The mandible hosts the lower teeth (their depth delineated by the alveolar process ). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels . Amongst other functions, the jawbone is essential for chewing food. Owing to

5424-538: The western swamp tortoise of Australia and a subcanopy conifer tree in the United States called Florida Torreya . A well-studied botanical example of a relictual taxon is Ginkgo biloba , the last living representative of Ginkgoales that is restricted to China in the wild. Ginkgo trees had a diverse and widespread northern distribution during the Mesozoic , but are not known from the fossil record after

5537-490: The Latin word mandibula 'jawbone' (literally, 'used for chewing'), from mandere 'to chew' and -bula ( instrumental suffix). In addition to mastication, the joint of the jawbone enables actions such speech and yawning , while playing a more subtle role in activities such as kissing and breathing . The mandible of vertebrates evolved from Meckel's cartilage , left and right segments of cartilage which supported

5650-685: The St. Lawrence-Great Lakes, including Georgian Bay , Lake Nipissing and Simcoe , Ontario, south to the Gulf of Mexico ; Atlantic and Gulf Coastal Plain from the Susquehanna River drainage in southeastern Pennsylvania to the Colorado River in Texas . Research from the late 1800s to the 1980s suggests a trend of intentional stockings of non-indigenous fish into ponds, lakes and rivers in

5763-689: The United States. At that time, little was known about environmental impacts, or long-term effects of new species establishment and spread as a result of "fish rescue and transfer" efforts, or the importance of nongame fish to the ecological balance of aquatic ecosystems. Introductions of bowfin to areas they were considered a non-indigenous species included various lakes, rivers and drainages in Connecticut, Delaware, Georgia, Illinois, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Virginia, West Virginia, and Wisconsin. Many of

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5876-417: The ability to breathe air. Their gill filaments and lamellae are rigid in structure which helps prevent the lamellae from collapsing and aids gas exchange even during air exposure. Competing hypotheses and debates continue over the evolution of Amia and relatives, including their relationship among basal extant teleosts, and organization of clades . Bowfin are the last remaining member of Halecomorphi ,

5989-407: The angle measuring from 110° to 120°, also the adult condyle is higher than the coronoid process and the sigmoid notch becomes deeper. The adult mandible is the skull's largest and strongest bone. In old age, the bone can become greatly reduced in volume where there is a loss of teeth, and consequent resorption of the alveolar process and interalveolar septa. Consequently, the chief part of the bone

6102-411: The anterior branchial arch in early fish . Fish jaws surface in species of the large arthrodire genus Dunkleosteus ( fl.  382–358 million years ago ), which crushed prey with their quickly articulating mouths. The lower jaw of cartilaginous fish , such as sharks , is composed of a cartilagenous structure homologous with Meckel's cartilage. This also remains a significant element of

6215-426: The anterior third, nearer its external surface. It contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth. The mandible has two main holes ( foramina ), found on both its left and right sides: The inferior alveolar nerve (IAN), a branch of the mandibular nerve (itself a major division of the cranium's trigeminal nerve ), enters the mandibular foramen and runs forward in

6328-426: The bowfin gills, that are then externally fertilized by sperm passing in the water flow. The small glochidia larvae then hatch and develop in the gill tubes. Bowfin with liver cancer and with fatal leukemia have been reported. As a sport fish, bowfin are not considered desirable to many anglers . They were once considered a nuisance fish by anglers and early biologists who believed the bowfin's predatory nature

6441-630: The bowfin is elongated and cylindrical, with the sides and back olive to brown in color, often with vertical bars and dark reticulations or another camouflaged pattern. The dorsal fin has horizontal bars, and the caudal fin has irregular vertical bars. The underside is white or cream, and the paired fins and anal fin are bright green. During larval stage, hatchlings from about 7–10 mm (0.28–0.39 in) total length are black and tadpole-like in appearance. At approximately 25 mm (0.98 in) total length they have been described as looking like miniature placoderms . They grow quickly, and typically leave

6554-413: The bowfin. Neopterygians are the second major occurrence in the evolution of ray-finned fish and today include the majority of modern bony fish. They are distinguished from their earlier ancestors by major changes to the jaws, shape of the skull, and tail. They are divided into three divisions: The following is a species list The bowfin genome contains an intact ParaHox gene cluster , similar to

6667-411: The canine tooth the cartilage disappears, while the portion of it below and behind the incisor teeth becomes ossified and incorporated with this part of the mandible. About the sixth week of fetal life, intramembranous ossification takes place in the membrane covering the outer surface of the ventral end of Meckel's cartilage, and each half of the bone is formed from a single center which appears, near

6780-456: The capacity to breathe both water and air. Their gills exchange gases in the water allowing them to breathe, but they also have a gas bladder that serves to maintain buoyancy, and also allows them to breathe air by means of a small pneumatic duct connected from the foregut to the gas bladder. They can break the surface to gulp air, which allows them to survive conditions of aquatic hypoxia that would be lethal to most other species. The bowfin

6893-543: The case of the white-eyed river martin , a very localized species of bird found only in Southeast Asia, and extremely rare, if not already extinct. Its closest and only surviving living relative is the African river martin , also very localized in central Africa. These two species are the only known members of the subfamily Pseudochelidoninae, and their widely disjunct populations suggest they are relict populations of

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7006-399: The center but raised on both sides to form the mental tubercle . Just above this, on both sides, the mentalis muscles attach to a depression called the incisive foramen . Vertically midway on either side of the body, below the second premolar tooth, is the mental foramen , through which the mental nerve and blood vessels pass. Running backward and upward from each mental tubercle is

7119-402: The chondrocranium, which is attached to the upper jaw, while adductor muscles act to close the lower jaw. This ability to open and close the jaw helps the bowfin to be an active predator that can catch bigger prey and digest them. The vertebral column in bowfin is ossified and in comparison to earlier fish, the centra are the major support for the body, whereas in earlier fish the notochord

7232-479: The consumption of fish caught in those areas. Concentration of mercury biomagnifies as it passes up the food chain from organisms on lower trophic levels to apex predators. It bioaccumulates in the tissues of larger, long-lived predatory fish. When compared to smaller, short-lived fish, bowfin tend to concentrate mercury at higher levels thereby making them less safe for human consumption. [REDACTED] Relict species A relict (or relic) plant or animal

7345-540: The dentary, only few other bones of the lower jaw remain in mammals; the former articular and quadrate bones survive as the malleus and the incus of the middle ear. In recent human evolution , both the oral cavity and jaws have shrunk in correspondence with the Neolithic-era shift from hunter-gatherer lifestyles towards agriculture and settlement, dated to c.  10,000 BCE . This has led to orthodontic malocclusions . The mandible forms as

7458-427: The eastern United States, and in southern Ontario and Quebec . Fossil deposits indicate Amiiformes were once widespread in both freshwater and marine environments across North and South America, Europe, Asia, and Africa. Now, their range is limited to much of the eastern United States and adjacent southern Canada, including the drainage basins of the Mississippi River , Great Lakes , and various rivers exiting in

7571-528: The fossil record would be a specimen of Nimravidae , an extinct branch of carnivores in the mammalian evolutionary tree, if said specimen came from Europe in the Miocene epoch. If that was the case, the specimen would represent, not the main population, but a last surviving remnant of the nimravid lineage. These carnivores were common and widespread in the previous epoch, the Oligocene , and disappeared when

7684-506: The fracturing risk they impose on teeth. Owing in part to the forensic evidence of Hitler's death being limited to his dental remains (including a jawbone fragment broken and burnt around the alveolar process), some fringe accounts (bolstered by the Soviet Union , which captured Berlin in 1945) allege that Hitler faked his death (ostensibly along with Eva Braun ). In later decades, American real-estate businessman Fred Trump had

7797-780: The gas bladder. Air breathing type I is consistent with the action of exhale / inhale exchange, stimulated by either air or water hypoxia , to regulate O 2 gas exchange; type II air breaths are inhalation alone, which is believed to regulate gas bladder volume, to control buoyancy . Bimodal respiration helps bowfin survive and maintain their metabolic rate in hypoxic (low-oxygen) conditions. Bowfin air breath more frequently when they are in darkness, and correspondingly more active. Bowfin blood can adapt to warm, acidic waters. The fish becomes inactive in waters below 10 °C (50 °F); at this temperature they breathe almost no air; however, with increasing temperature their air breathing increases. Their preferred temperature range

7910-468: The gill easily. Its structure alone indicated that the Amia do not use microorganisms as a source of food. Fossil deposits indicate amiiforms included freshwater and marine species that were once widely distributed in North America, South America, Eurasia and Africa. Today, bowfin ( Amia calva ) are the only remaining species in the order Amiiformes; they are demersal freshwater piscivores , and their range

8023-415: The human mandible has four sides, two surfaces, four borders, and two processes. On the outside, the ramus is flat and marked by oblique ridges at its lower part. It gives attachment throughout nearly the whole of its extent to the masseter muscle. On the inside at the center there is an oblique mandibular foramen , for the entrance of the inferior alveolar vessels and nerve . The margin of this opening

8136-704: The introductions were intentional stockings; however, there is no way to positively determine distribution resulting from flood transfers, or other inadvertent migrations. Bowfin are typically piscivorous, but as an introduced species are capable of being voracious predators that pose a threat to native fish and their prey. Bowfin prefer vegetated sloughs, lowland rivers and lakes, swamps, backwater areas, and are occasionally found in brackish water. They are well camouflaged, and not easy to spot in slow water with abundant vegetation. They often seek shelter under roots, and submerged logs. Oxygen-poor environments can be tolerated because of their ability to breathe air. Bowfin spawn in

8249-482: The jaw in some primitive bony fish, such as sturgeons . In reptiles , Meckel's cartilage ossifies into the (multiple) bones of the lower jaw, while mammals of the Cretaceous (145–66 Mya) had both Meckel's cartilage and a mandible. In lobe-finned fishes and the early fossil tetrapods , the bone homologous to the mandible of mammals is merely the largest of several bones in the lower jaw. In such animals, it

8362-429: The jaws by the teeth; about the fourth year it is 140°. The fibrocartilage of the mandibular symphysis fuses together in early childhood. In the adult, the alveolar and subdental portions of the body are usually of equal depth. The mental foramen opens midway between the upper and lower borders of the bone, and the mandibular canal runs nearly parallel with the mylohyoid line. The ramus is almost vertical in direction,

8475-423: The late 19th century with new techniques for attaching prosthetics to a depreciated jawbone as well as bone grafting. In 2010, the first successful face transplant was conducted on a Spanish farmer after a self-inflicted gun accident ; this included the replacement of the entire mandible. The mandible can provide forensic evidence because its form changes over a person's life, and this can be used to determine

8588-568: The limbs of tetrapods. Bowfin are physostomes , meaning they have a small " pneumatic duct " that connects their swim bladders to their digestrive tract. This allows them, like lungfish , to "breath" in two ways: they can extract oxygen from the water when breathing through their gills , but can also break the water's surface to breathe or gulp air through the pneumatic duct . When performing low-level physical activity, bowfin obtain more than half of their oxygen from breathing air. The fish have two distinct air-breathing mechanisms used to ventilate

8701-465: The lower jaw: the dentary, the angular, and the surangular. The cranial surface of the skull is made up of the nasals, the antorbital, the lacrimal, the parietal, the intertemporal, the post parietal, the supratemporal, the extra scapular, the post temporal, and the opercular. The entirety of the skull is attached to the girdle through another set of bones. Bowfin are often referred to as " living fossils " or " primitive fish " because they retained some of

8814-410: The lower symphysis is a ridge called the mylohyoid line , where the mylohyoid muscle attaches; a small part of the superior pharyngeal constrictor muscle attaches to the posterior ridge, near the alveolar margin . Above the anterior ridge, the sublingual gland rests against a smooth triangular area, and below the posterior ridge, the submandibular gland rests in an oval depression. The ramus of

8927-403: The mandible and its teeth, making it a target of block anesthesia . Injecting the nerve is challenging due to the amount of surrounding soft tissue . American surgeon William Stewart Halsted developed a technique using a syringe and cocaine which was performed successfully by 1885. One fifth of facial injuries involve a mandibular fracture. Mandibular fractures are often accompanied by

9040-413: The mandible is curved, and the front part gives structure to the chin . It has two surfaces and two borders. From the outside, the mandible is marked in the midline by a faint ridge, indicating the mandibular symphysis , the line of junction of the two halves of the mandible. This ridge divides below and encloses a triangular eminence, the mental protuberance (the chin), the base of which is depressed in

9153-412: The mandible is the largest and lowest bone in the facial skeleton . It is the only movable bone of the skull (discounting the vibrating ossicles of the middle ear ). It is connected to the skull's temporal bones by the temporomandibular joints . In addition to simply opening and closing, the jawbone can articulate side to side as well as forward and back. The mandible consists of: The body of

9266-414: The mandibular arch (occasionally noted also in partially edentulous cases). This resorption can occur to such an extent that the mental foramen is virtually on the superior border of the mandible, instead of opening on the anterior surface, changing its relative position. However, the more inferior body of the mandible is not affected and remains thick and rounded. With age and tooth loss, the alveolar process

9379-459: The mandibular canal, supplying sensation to the gums and teeth. Before passing through the mental foramen, the nerve divides into two terminal branches: incisive and mental nerves. The incisive nerve runs forward in the mandible and supplies the anterior teeth. The mental nerve exits the mental foramen and supplies sensation to the chin and lower lip. Males generally have squarer, stronger, and larger mandibles than females. The mental protuberance

9492-467: The mental foramen. By the tenth week, the portion of Meckel's cartilage which lies below and behind the incisor teeth is surrounded and invaded by the dermal bone (also known as the membrane bone). Somewhat later, accessory nuclei of cartilage make their appearance, as These accessory nuclei possess no separate ossific centers but are invaded by the surrounding dermal bone and undergo absorption. The inner alveolar border, usually described as arising from

9605-475: The most primitive actinopterygians , the scales of bowfin differ in that they are not ganoid scales , rather they are large, single-layered cycloid scales closer in similarity to more derived teleosts . Northern snakeheads ( Channa argus ) are commonly mistaken for bowfin because of similarities in appearance, most noticeably their elongated, cylindrical shape, and long dorsal fin that runs along their backs. Northern snakeheads are piscivorous fish native to

9718-482: The mouth is made up of three bones, the ectopterygoid, the palantine, and the vomer. They have two sets of teeth, including one set of larger sharp teeth coming out of the mandibular and premaxillary bones to grasp and control the prey. The other set of teeth, located posteriorly and connected to the hyomandibular bone, is made up of pharyngeal tooth patches, which are used for sorting out nutrients and grinding down larger pieces of food. Another three bones make up

9831-473: The nest after spawning, leaving the male behind to protect the eggs during the eight to ten days of incubation. A nest may contain 2,000 to 5,000 eggs, possibly more. Fecundity is usually related to size of the fish, so it is not unusual for the roe of a large gravid female to contain over 55,000 eggs. Bowfin eggs are adhesive, and will attach to aquatic vegetation, roots, gravel, and sand. After hatching, larval bowfin do not swim actively in search of food. During

9944-430: The nest within 4 to 6 weeks after hatching. Young males have a black eyespot on the base of the tail ( caudal peduncle ) that is commonly encircled by an orange-yellowish border, while the female's is black, if present at all. It is thought the purpose of the eyespot is to confuse predators, deflecting attacks away from the head of the fish to its tail, which affords the bowfin an opportunity to escape predation. The bowfin

10057-438: The nest. The ritual consists of intermittent nose bites, nudges, and chasing behavior by the male until the female becomes receptive, at which time the pair lie side by side in the nest. She deposits her eggs while he shakes his fins in a vibratory movement, and releases his milt for fertilization to occur. A male often has eggs from more than one female in his nest, and a single female often spawns in several nests. Females vacate

10170-475: The parent male bowfin who slowly circles them to prevent separation. Bowfin reach sexually maturity at two to three years of age. They can live up to 33 years in the wild, and 30 years in captivity. Bowfin may live decades at adult size. A common parasite of bowfin is the anchor worm ( Lernaea ). These small crustaceans infest the skin and bases of fins, with consequences ranging from slowed growth to death. The mollusk Megalonaias gigantea lays eggs in

10283-490: The past for various purposes (medicinal, food, dyes, etc.), but are no longer utilized. They are naturalized and can be found at archaeological sites. Mandible In jawed vertebrates , the mandible (from the Latin mandibula , 'for chewing'), lower jaw , or jawbone is a bone that makes up the lower – and typically more mobile – component of the mouth (the upper jaw being known as

10396-411: The powerful action of the masticatory muscles; but, the alveolar portion is the deeper of the two, and, consequently, the chief part of the body lies above the oblique line. The mandibular canal, after the second dentition, is situated just above the level of the mylohyoid line ; and the mental foramen occupies the position usual to it in the adult. The angle becomes less obtuse, owing to the separation of

10509-413: The prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular. Most vertebrates exhibit a simpler scheme, as bones have either fused or vanished. In teleosts , only the dentary, articular, and angular bones remain, while in living amphibians , the dentary is accompanied only by

10622-607: The prearticular, and, in salamanders , one of the coronoids. The lower jaw of reptiles has only a single coronoid and splenial, but retains all the other primitive bones except the prearticular and the periosteum. In birds, the various bones have fused into a single structure. In mammals, most have disappeared, leaving only the mandible. As a result, there is only articulation between the mandible and temporal bones, as opposed to articulation between articular and quadrate bones . An intermediate stage can be seen in some therapsids , in which both points of articulation are present. Aside from

10735-465: The primitive characters common to their ancestors, including a modified (rounded externally) heterocercal caudal fin , a highly vascularized gas bladder lung, vestiges of a spiral valve , and a bony gular plate. The bony gular plate is located underneath the head on the exterior of the lower jaw between the two sides of the lower jaw bone. Other distinguishing characteristics include long, sharp teeth, and two protruding tube-like nostrils. Unlike all of

10848-414: The ramus, and then horizontally forward in the body, where it is placed under the alveoli , with small openings for nerves. On arriving at the incisor teeth , it turns back to communicate with the mental foramen, giving off two small canals which run to the cavities containing the incisor teeth. In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible; and in

10961-413: The range of the population was not always restricted to the local region. In other words, the species or group did not necessarily arise in that small area, but rather was stranded, or insularized, by changes over time. The agent of change could be anything from competition from other organisms, continental drift , or climate change such as an ice age . When a relict is representative of taxa found in

11074-400: The rivers and estuaries of China, Russia, and Korea that have been introduced and become established in parts of North America. However, unlike bowfin which are native to North America, the northern snakehead is considered an invasive species and environmentally harmful there. Some contrasting differences in bowfin include a black eyespot on their caudal peduncle, a tan and olive coloration,

11187-400: The same time creating barriers for biological dispersal . Studies have shown that such insular habitats have a tendency toward decreasing species richness . This observation has significant implications for conservation biology, because habitat fragmentation can also lead to the insularization of stranded populations. So-called "relics of cultivation" are plant species that were grown in

11300-410: The second year, near the alveolar margin. The body becomes elongated in its whole length, but more especially behind the mental foramen, to provide space for the three additional teeth developed in this part. The depth of the body increases owing to increased growth of the alveolar part, to afford room for the roots of the teeth, and by thickening of the subdental portion which enables the jaw to withstand

11413-408: The seven to nine days required for yolk-sac absorption, they attach to vegetation by means of an adhesive organ on their snout, and remain protected by the parent male bowfin. Bowfin aggressively protect their spawn from the first day of incubation to a month or so after the eggs have hatched. When the fry are able to swim and forage on their own, they will form a school and leave the nest accompanied by

11526-407: The socket of the first deciduous molar tooth. The angle is obtuse (175°), and the condyloid portion is nearly in line with the body. The coronoid process is of comparatively large size, and projects above the level of the condyle. After birth, the two segments of the bone become joined at the symphysis, from below upward, in the first year; but a trace of separation may be visible in the beginning of

11639-443: The spring or early summer, typically between April and June, more commonly at night in abundantly vegetated, clear shallow water in weed beds over sand bars, and also under stumps, logs, and bushes. Optimum temperatures for nesting and spawning range between 16–19 °C (61–66 °F). The males construct circular nests in fibrous root mats, clearing away leaves and stems. Depending on the density of surrounding vegetation there may be

11752-431: The subclass Actinopterygii include 42 orders, 431 families and over 23,000 species. They are currently classified into two infraclasses, Chondrostei ( holosteans ) and Neopterygii (teleost fishes). Sturgeons, paddlefish, bichirs and reed fish compose the thirty-eight species of chondrosteans, and are considered relict species. Included in the over 23,000 species of neopterygians are eight relict species comprising gars and

11865-491: The superior (upper) and posterior projection from the ramus, makes the temporomandibular joint with the temporal bone. The coronoid process, superior and anterior projection from the ramus. This provides attachment to the temporal muscle . Teeth sit in the upper part of the body of the mandible. The frontmost part of teeth is more narrow and holds front teeth. The back part holds wider and flatter (albeit grooved) teeth primarily for chewing food. The word mandible derives from

11978-512: The temporomandibular joint prevents the mandible from moving posteriorly, making the condylar neck particularly vulnerable to fractures. Further, various jawbone damage can cause temporomandibular joint dysfunction , with symptoms including pain and inflammation . The jawbone can also become deviated in mandibular lateral displacement , a condition which can offset facial symmetry and cause posterior crossbite . The mandibular alveolar process can become resorbed when completely edentulous in

12091-592: The warming climate will cause the lily to die out in Great Britain . Other populations of the same plant can be found in the Arctic and in the mountains of Europe and North America, where it is known as the common alplily. While the extirpation of a geographically disjunct population of a relict species may be of regional conservation concern, outright extinction at the species level may occur in this century of rapid climate change if geographic range occupied by

12204-460: The water, and they have a voracious appetite. Their undulating dorsal fin propels them silently through the water while stalking their prey. The attack is straightforward and swift with a movement that lasts approximately 0.075 seconds. There were also some studies regarding the capacity of the bowfin to survive without food. In 1916, a female bowfin was starved for twenty months. It was the longest period that any vertebrate had been without food, as far

12317-406: The wild, and cultured commercially in hatcheries for their meat and roe. The roe is processed into caviar, and sold as "Cajun caviar", or marketed under the trade name "Choupiquet Royale". In some areas of the United States where aquatic environments have tested positive for elevated levels of toxins , such as mercury , arsenic , chromium , and copper , there are posted signs with warnings about

12430-399: The writer was aware during the observation. Some independent studies focus on the bowfin's ability to use organic material as a source of food and studied the structure of the gill raker . They concluded that it did not benefit from the organic material in the water because the gill rakers were short with blunt processes and a short space between them. Even bacteria could enter and exit through

12543-513: The years, global efforts have imposed strict regulations on the international trade of caviar, particularly on the harvest of sturgeons from the Caspian Sea where the highly prized caviar from the beluga sturgeon originates. The bans imposed on Caspian sturgeons have created lucrative markets for affordable substitutes in the United States including paddlefish , bowfin, and various species of sturgeon . In Louisiana , bowfin are harvested in

12656-400: Was harmful to sport fish populations. As a result, efforts were taken to reduce their numbers. Research has since proven otherwise, and that knowledge together with a better understanding of maintaining overall balance of ecosystems, regulations were introduced to help protect and maintain viable populations of bowfin. Bowfin are strong fighters, a prized trait in game fish. However, they do have

12769-440: Was the main form of support. In bowfin neural spines and ribs also increase in prominence, an evolutionary aspect that helps provide additional support and stabilize unpaired fins. The evolution of the vertebral column allows the bowfin to withstand lateral bending that puts the column under compression without breaking. This, in turn, allows the bowfin to have more controlled and powerful movements, in comparison to fish that had only

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