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50-427: See text Anablepidae is a family of ray-finned fishes which live in brackish and freshwater habitats from southern Mexico to southern South America . There are three genera with sixteen species : the four-eyed fishes (genus Anableps ), the onesided livebearers (genus Jenynsia ) and the white-eye , Oxyzygonectes dovii . Fish of this family eat mostly insects and other invertebrates . Fish in

100-468: A false sea floor 300–500 metres deep at day, and less deep at night. This turned out to be due to millions of marine organisms, most particularly small mesopelagic fish, with swimbladders that reflected the sonar. These organisms migrate up into shallower water at dusk to feed on plankton. The layer is deeper when the moon is out, and can become shallower when clouds obscure the moon. Most mesopelagic fish make daily vertical migrations , moving at night into

150-459: A free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism . In most cases this involves protogyny , fish starting life as females and converting to males at some stage, triggered by some internal or external factor. Protandry , where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization . Of

200-420: A gas bladder. Physoclisti can not expel air quickly enough from the gas bladder, the organ most susceptible to sonic damage, thus making it difficult for them to escape major injury. Physostomes, on the other hand, can release air from their gas bladder expeditiously enough to protect it; nevertheless, they can not relieve pressure in their other vital organs, and are therefore also vulnerable to injury. Some of

250-414: A large range of depths. Due to the dorsal position it gives the fish lateral stability. In physostomous swim bladders, a connection is retained between the swim bladder and the gut , the pneumatic duct, allowing the fish to fill up the swim bladder by "gulping" air. Excess gas can be removed in a similar manner. In more derived varieties of fish (the physoclisti ), the connection to the digestive tract

300-742: A trait still present in Holostei ( bowfins and gars ). In some fish like the arapaima , the swim bladder has been modified for breathing air again, and in other lineages it have been completely lost. The teleosts have urinary and reproductive tracts that are fully separated, while the Chondrostei have common urogenital ducts, and partially connected ducts are found in Cladistia and Holostei. Ray-finned fishes have many different types of scales ; but all teleosts have leptoid scales . The outer part of these scales fan out with bony ridges, while

350-587: Is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia , as opposed to the bulkier, fleshy lobed fins of the sister class Sarcopterygii (lobe-finned fish). Resembling folding fans , the actinopterygian fins can easily change shape and wetted area , providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to

400-545: Is divided into the infraclasses Holostei and Teleostei . During the Mesozoic ( Triassic , Jurassic , Cretaceous ) and Cenozoic the teleosts in particular diversified widely. As a result, 96% of living fish species are teleosts (40% of all fish species belong to the teleost subgroup Acanthomorpha ), while all other groups of actinopterygians represent depauperate lineages. The classification of ray-finned fishes can be summarized as follows: The cladogram below shows

450-445: Is divided into two subfamilies and three genera: This Cyprinodontiformes article is a stub . You can help Misplaced Pages by expanding it . Ray-finned fish Actinopterygii ( / ˌ æ k t ɪ n ɒ p t ə ˈ r ɪ dʒ i aɪ / ; from actino-  'having rays' and Ancient Greek πτέρυξ (ptérux)  'wing, fins'), members of which are known as ray-finned fish or actinopterygians ,

500-518: Is evolutionarily homologous to the lungs of tetrapods and lungfish , and some ray-finned fish such as bowfins have also evolved similar respiratory functions in their swim bladders. Charles Darwin remarked upon this in On the Origin of Species , and reasoned that the lung in air-breathing vertebrates had derived from a more primitive swim bladder as a specialized form of enteral respiration . In

550-430: Is lost. In early life stages, these fish must rise to the surface to fill up their swim bladders; in later stages, the pneumatic duct disappears, and the gas gland has to introduce gas (usually oxygen ) to the bladder to increase its volume and thus increase buoyancy . This process begins with the acidification of the blood in the rete mirabile when the gas gland excretes lactic acid and produces carbon dioxide ,

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600-432: Is relatively rare and is found in about 6% of living teleost species; male care is far more common than female care. Male territoriality "preadapts" a species for evolving male parental care. There are a few examples of fish that self-fertilise. The mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to

650-491: The Actinopteri (ray-finned fish minus the bichirs ) the lungs evolved into a swim bladder (secondary absent in some lineages), which unlike lungs that bud ventrally, buds dorsally from the anterior foregut. Coelacanths have a "fatty organ" that have sometimes been referred to as a swim bladder, but is structurally different and have a separate evolutionary history. In 1997, Farmer proposed that lungs evolved to supply

700-506: The Cyprinidae (in goldfish and common carp as recently as 14 million years ago). Ray-finned fish vary in size and shape, in their feeding specializations, and in the number and arrangement of their ray-fins. In nearly all ray-finned fish, the sexes are separate, and in most species the females spawn eggs that are fertilized externally, typically with the male inseminating the eggs after they are laid. Development then proceeds with

750-592: The deep sea to subterranean waters to the highest mountain streams . Extant species can range in size from Paedocypris , at 8 mm (0.3 in); to the massive ocean sunfish , at 2,300 kg (5,070 lb); and to the giant oarfish , at 11 m (36 ft). The largest ever known ray-finned fish, the extinct Leedsichthys from the Jurassic , has been estimated to have grown to 16.5 m (54 ft). Ray-finned fishes occur in many variant forms. The main features of typical ray-finned fish are shown in

800-455: The dorsal portion of the fish, although in a few primitive species, there is only a single sac. It has flexible walls that contract or expand according to the ambient pressure . The walls of the bladder contain very few blood vessels and are lined with guanine crystals, which make them impermeable to gases. By adjusting the gas pressurising organ using the gas gland or oval window, the fish can obtain neutral buoyancy and ascend and descend to

850-560: The macula of saccule in order for the inner ear to receive a sensation from the sound pressure. In red-bellied piranha , the swim bladder may play an important role in sound production as a resonator. The sounds created by piranhas are generated through rapid contractions of the sonic muscles and is associated with the swim bladder. Teleosts are thought to lack a sense of absolute hydrostatic pressure , which could be used to determine absolute depth. However, it has been suggested that teleosts may be able to determine their depth by sensing

900-488: The oviparous teleosts, most (79%) do not provide parental care. Viviparity , ovoviviparity , or some form of parental care for eggs, whether by the male, the female, or both parents is seen in a significant fraction (21%) of the 422 teleost families; no care is likely the ancestral condition. The oldest case of viviparity in ray-finned fish is found in Middle Triassic species of † Saurichthys . Viviparity

950-463: The saccule and the lagena . They are suited for detecting sound and vibrations due to its low density in comparison to the density of the fish's body tissues. This increases the ability of sound detection. The swim bladder can radiate the pressure of sound which help increase its sensitivity and expand its hearing. In some deep sea fishes like the Antimora , the swim bladder maybe also connected to

1000-663: The sister lineage of all other actinopterygians, the Acipenseriformes (sturgeons and paddlefishes) are the sister lineage of Neopterygii, and Holostei (bowfin and gars) are the sister lineage of teleosts. The Elopomorpha ( eels and tarpons ) appear to be the most basal teleosts. The earliest known fossil actinopterygian is Andreolepis hedei , dating back 420 million years ( Late Silurian ), remains of which have been found in Russia , Sweden , and Estonia . Crown group actinopterygians most likely originated near

1050-949: The Devonian-Carboniferous boundary. The earliest fossil relatives of modern teleosts are from the Triassic period ( Prohalecites , Pholidophorus ), although it is suspected that teleosts originated already during the Paleozoic Era . The listing below is a summary of all extinct (indicated by a dagger , †) and living groups of Actinopterygii with their respective taxonomic rank . The taxonomy follows Phylogenetic Classification of Bony Fishes with notes when this differs from Nelson, ITIS and FishBase and extinct groups from Van der Laan 2016 and Xu 2021. [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Swim bladder The swim bladder

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1100-402: The adjacent diagram. The swim bladder is a more derived structure and used for buoyancy . Except from the bichirs , which just like the lungs of lobe-finned fish have retained the ancestral condition of ventral budding from the foregut , the swim bladder in ray-finned fishes derives from a dorsal bud above the foregut. In early forms the swim bladder could still be used for breathing,

1150-478: The arteries supplying the gas gland via a countercurrent multiplication loop . Thus a very high gas pressure of oxygen can be obtained, which can even account for the presence of gas in the swim bladders of deep sea fish like the eel , requiring a pressure of hundreds of bars . Elsewhere, at a similar structure known as the 'oval window', the bladder is in contact with blood and the oxygen can diffuse back out again. Together with oxygen, other gases are salted out in

1200-463: The bichirs and holosteans (bowfin and gars) in having gone through a whole-genome duplication ( paleopolyploidy ). The WGD is estimated to have happened about 320 million years ago in the teleosts, which on average has retained about 17% of the gene duplicates, and around 180 (124–225) million years ago in the chondrosteans. It has since happened again in some teleost lineages, like Salmonidae (80–100 million years ago) and several times independently within

1250-454: The bladder would burst. Physostomes can "burp" out gas, though this complicates the process of re-submergence. The swim bladder in some species, mainly fresh water fishes ( common carp , catfish , bowfin ) is interconnected with the inner ear of the fish. They are connected by four bones called the Weberian ossicles from the Weberian apparatus . These bones can carry the vibrations to

1300-443: The clarification of beer . In earlier times, they were used to make condoms . Swim bladder disease is a common ailment in aquarium fish . A fish with swim bladder disorder can float nose down tail up, or can float to the top or sink to the bottom of the aquarium. Many anthropogenic activities, such as pile driving or even seismic waves , can create high-intensity sound waves that cause internal injury to fish that possess

1350-534: The commonly seen injuries include ruptured gas bladder and renal Haemorrhage . These mostly affect the overall health of the fish but not their mortality rate. Investigators employed the High-Intensity-Controlled Impedance-Fluid-Filled (HICI-FT), a stainless-steel wave tube with an electromagnetic shaker. It simulates high-energy sound waves in aquatic far-field, plane-wave acoustic conditions. Siphonophores have

1400-706: The different actinopterygian clades (in millions of years , mya) are from Near et al., 2012. Jaw-less fishes ( hagfish , lampreys ) [REDACTED] Cartilaginous fishes ( sharks , rays , ratfish ) [REDACTED] Coelacanths [REDACTED] Lungfish [REDACTED] Amphibians [REDACTED] Mammals [REDACTED] Sauropsids ( reptiles , birds ) [REDACTED] Polypteriformes ( bichirs , reedfishes ) [REDACTED] Acipenseriformes ( sturgeons , paddlefishes ) [REDACTED] Teleostei [REDACTED] Amiiformes ( bowfins ) [REDACTED] Lepisosteiformes ( gars ) [REDACTED] The polypterids (bichirs and reedfish) are

1450-452: The embryonic stages, some species, such as redlip blenny , have lost the swim bladder again, mostly bottom dwellers like the weather fish . Other fish — like the opah and the pomfret — use their pectoral fins to swim and balance the weight of the head to keep a horizontal position. The normally bottom-dwelling sea robin can use their pectoral fins to produce lift while swimming like cartilaginous fish do. The gas/tissue interface at

1500-407: The epipelagic zone, often following similar migrations of zooplankton, and returning to the depths for safety during the day. These vertical migrations often occur over large vertical distances, and are undertaken with the assistance of a swim bladder. The swim bladder is inflated when the fish wants to move up, and, given the high pressures in the mesoplegic zone, this requires significant energy. As

1550-508: The fish ascends, the pressure in the swimbladder must adjust to prevent it from bursting. When the fish wants to return to the depths, the swimbladder is deflated. Some mesopelagic fishes make daily migrations through the thermocline , where the temperature changes between 10 and 20 °C, thus displaying considerable tolerance for temperature change. Sampling via deep trawling indicates that lanternfish account for as much as 65% of all deep sea fish biomass . Indeed, lanternfish are among

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1600-432: The fish's habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C (66 °F) and can fertilise eggs that are then spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred. Actinopterygii is divided into the subclasses Cladistia , Chondrostei and Neopterygii . The Neopterygii , in turn,

1650-439: The heart with oxygen. In fish, blood circulates from the gills to the skeletal muscle, and only then to the heart. During intense exercise, the oxygen in the blood gets used by the skeletal muscle before the blood reaches the heart. Primitive lungs gave an advantage by supplying the heart with oxygenated blood via the cardiac shunt. This theory is robustly supported by the fossil record, the ecology of extant air-breathing fishes, and

1700-438: The inner part is crossed with fibrous connective tissue. Leptoid scales are thinner and more transparent than other types of scales, and lack the hardened enamel - or dentine -like layers found in the scales of many other fish. Unlike ganoid scales , which are found in non-teleost actinopterygians, new scales are added in concentric layers as the fish grows. Teleosts and chondrosteans (sturgeons and paddlefish) also differ from

1750-404: The latter of which acidifies the blood via the bicarbonate buffer system . The resulting acidity causes the hemoglobin of the blood to lose its oxygen ( Root effect ) which then diffuses partly into the swim bladder. Before returning to the body, the blood re-enters the rete mirabile , and as a result, virtually all the excess carbon dioxide and oxygen produced in the gas gland diffuses back to

1800-466: The main clades of living actinopterygians and their evolutionary relationships to other extant groups of fishes and the four-limbed vertebrates ( tetrapods ). The latter include mostly terrestrial species but also groups that became secondarily aquatic (e.g. whales and dolphins ). Tetrapods evolved from a group of bony fish during the Devonian period . Approximate divergence dates for

1850-581: The millions of lanternfish swim bladders, giving the appearance of a false bottom. In the East Asian culinary sphere, the swim bladders of certain large fishes are considered a food delicacy. In Chinese cuisine, they are known as fish maw , 花膠/鱼鳔, and are served in soups or stews. The vanity price of a vanishing kind of maw is behind the imminent extinction of the vaquita , the world's smallest porpoise species. Found only in Mexico's Gulf of California ,

1900-399: The most widely distributed, populous, and diverse of all vertebrates , playing an important ecological role as prey for larger organisms. The estimated global biomass of lanternfish is 550–660 million tonnes , several times the annual world fisheries catch. Lanternfish also account for much of the biomass responsible for the deep scattering layer of the world's oceans. Sonar reflects off

1950-407: The necessary lift needed due to the lack of swim bladders. Teleost fish with swim bladders have neutral buoyancy, and have no need for this lift. The swim bladder of a fish can strongly reflect sound of an appropriate frequency. Strong reflection happens if the frequency is tuned to the volume resonance of the swim bladder. This can be calculated by knowing a number of properties of the fish, notably

2000-407: The once numerous vaquita are now critically endangered. Vaquita die in gillnets set to catch totoaba (the world's largest drum fish ). Totoaba are being hunted to extinction for its maw, which can sell for as much $ 10,000 per kilogram. Swim bladders are also used in the food industry as a source of collagen . They can be made into a strong, water-resistant glue, or used to make isinglass for

2050-431: The physiology of extant fishes. In embryonal development, both lung and swim bladder originate as an outpocketing from the gut; in the case of swim bladders, this connection to the gut continues to exist as the pneumatic duct in the more "primitive" ray-finned fish, and is lost in some of the more derived teleost orders. There are no animals which have both lungs and a swim bladder. As an adaptation to migrations between

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2100-494: The proximal or basal skeletal elements, the radials, which represent the articulation between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). The vast majority of actinopterygians are teleosts . By species count, they dominate the subphylum Vertebrata , and constitute nearly 99% of the over 30,000 extant species of fish . They are the most abundant nektonic aquatic animals and are ubiquitous throughout freshwater and marine environments from

2150-421: The rate of change of swim-bladder volume. The illustration of the swim bladder in fishes ... shows us clearly the highly important fact that an organ originally constructed for one purpose, namely, flotation, may be converted into one for a widely different purpose, namely, respiration. The swim bladder has, also, been worked in as an accessory to the auditory organs of certain fishes. All physiologists admit that

2200-403: The subfamily Oxyzygonectinae are ovoviviparous . The Anablepinae are livebearers . They mate on one side only, right-"handed" males with left-"handed" females and vice versa. The male has specialized anal rays which are greatly elongated and fused into a tube called a gonopodium associated with the sperm duct which he uses as an intromittent organ to deliver sperm to the female. The family

2250-479: The surface and deeper waters, some fish have evolved a swim bladder where the gas is replaced with low-density wax esters as a way to cope with Boyle's law . The cartilaginous fish (e.g., sharks and rays) split from the other fishes about 420 million years ago, and lack both lungs and swim bladders, suggesting that these structures evolved after that split. Correspondingly, these fish also have both heterocercal and stiff, wing-like pectoral fins which provide

2300-491: The swim bladder produces a strong reflection of sound, which is used by sonar equipment to find fish . Cartilaginous fish, such as sharks and rays , do not have swim bladders. Some of them can control their depth only by swimming (using dynamic lift ); others store up lipids with density less than that of seawater to produce a neutral or near-neutral buoyancy, which cannot be readily changed with depth. The swim bladder normally consists of two gas-filled sacs located in

2350-525: The swim bladder which accounts for the high pressures of other gases as well. The combination of gases in the bladder varies. In shallow water fish, the ratios closely approximate that of the atmosphere , while deep sea fish tend to have higher percentages of oxygen. For instance, the eel Synaphobranchus has been observed to have 75.1% oxygen, 20.5% nitrogen , 3.1% carbon dioxide , and 0.4% argon in its swim bladder. Physoclist swim bladders have one important disadvantage: they prohibit fast rising, as

2400-439: The swimbladder is homologous, or “ideally similar” in position and structure with the lungs of the higher vertebrate animals: hence there is no reason to doubt that the swim bladder has actually been converted into lungs, or an organ used exclusively for respiration. According to this view it may be inferred that all vertebrate animals with true lungs are descended by ordinary generation from an ancient and unknown prototype, which

2450-452: The volume of the swim bladder, although the well-accepted method for doing so requires correction factors for gas-bearing zooplankton where the radius of the swim bladder is less than about 5 cm. This is important, since sonar scattering is used to estimate the biomass of commercially- and environmentally-important fish species. Sonar operators, using the newly developed sonar technology during World War II, were puzzled by what appeared to be

2500-497: Was furnished with a floating apparatus or swim bladder. Charles Darwin , 1859 Swim bladders are evolutionarily closely related (i.e., homologous ) to lungs . The first lungs originated in the last common ancestor of the Actinopterygii (ray-finned fish) and Sarcopterygii (lobe-finned fish and the tetrapods ) as expansions of the upper digestive tract which allowed them to gulp air under oxygen-poor conditions. In

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