40-488: Ductor is an extinct genus of prehistoric ray-finned fish that lived from the early to middle Eocene . Fossils are found in Monte Bolca . In life, species of Ductor would have resembled pilot fish , though, they are more closely related to the jackfish . Some experts place Ductor into its own family, "Ductoridae," while others place the genus within the closely related Carangidae . This article about
80-409: A Bouligand -type arrangement. In a structure similar to plywood, the fibres in each successive layer are oriented at large angles to those in the previous layer, increasing toughness. The hard, corrugated surface of the outer layer, and the tough internal collagen layers work synergistically to contribute to their ability to flex and deform while providing strength and protection—a solution that allows
120-639: A prehistoric bony fish 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 , 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
160-458: A 30 kg specimen was found floating in the river in Angkor Wat area, Krovanh village, Sangkat Norkor Thom, Siem Reap, Cambodia ; the locals said it was a rare fish, and not commonly seen in this area. With catch-and-release after the fish is landed, it must be held for 5 minutes until it takes a breath. The fish has a large blood vessel running down its spine, so lifting the fish clear of
200-468: A consequence of this taxonomic confusion, most earlier studies were done using the name A. gigas , but this species is only known from old museum specimens and the exact native range is unclear. The regularly seen and studied species is A. arapaima , although a small number of A. leptosoma also have been recorded in the aquarium trade . The remaining species are virtually unknown: A. agassizii from old detailed drawings (the type specimen itself
240-459: 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
280-461: A nest about 50 cm (20 in) wide and 15 cm (5.9 in) deep, usually in muddy-bottomed areas. As the water rises, the eggs hatch and the offspring have the flood season from May to August in which to prosper, such that yearly spawning is regulated seasonally. The arapaima male is a mouthbrooder , like the related Osteoglossum genus, meaning the young are protected in his mouth until they are older. The female arapaima helps to protect
320-742: 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
360-533: Is an air breather , using its labyrinth organ , which is rich in blood vessels and opens into the fish's mouth, an advantage in oxygen-deprived water that is often found in the Amazon River . This fish is able to survive in oxbow lakes with dissolved oxygen as low as 0.5 ppm. In the wetlands of the Araguaia , one of the most important refuges for this species, it is the top predator in such lakes during
400-578: Is any large species of bonytongue in the genus Arapaima native to the Amazon and Essequibo basins of South America. Arapaima is the type genus of the subfamily Arapaiminae within the family Osteoglossidae . They are among the world's largest freshwater fish, reaching as much as 3 m (9.8 ft) in length. They are an important food fish. They have declined in the native range due to overfishing and habitat loss. In contrast, arapaima have been introduced to several tropical regions outside
440-471: Is deemed impossible, and thus considered questionable. As a result of overfishing, arapaima more than 2 m (6 ft 7 in) are seldom found in the wild. The arapaima is torpedo -shaped, with large, blackish-green scales and red markings. It is streamlined and sleek, with its dorsal and anal fins set near its tail. Arapaima scales have a mineralised, hard, outer layer with a corrugated surface under which lie several layers of collagen fibres in
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#1732771837575480-545: 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
520-489: Is grated and mixed into water. Doses are given to kill intestinal worms . The bony tongue is used to scrape cylinders of dried guarana, an ingredient in some beverages, and the bony scales are used as nail files. Arapaima produce boneless steaks and are considered a delicacy. In the Amazon region, locals often salt and dry the meat, rolling it into a cigar-style package that is then tied and can be stored without rotting, which
560-500: Is important in a region with little refrigeration. Arapaima are referred to as the "cod of the Amazon", and can be prepared in the same way as traditional salted cod. Designers have begun using the skin of the arapaima as leather to make jackets, shoes, and handbags, and to cover furniture. In July 2009, villagers around Kenyir Lake in Terengganu , Malaysia, reported sighting A. gigas . The "Kenyir monster", or "dragon fish" as
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
640-506: 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
680-671: The Miocene Villavieja Formation of Colombia . Museum specimens are found in France, England, the United States, Brazil, Guyana, Ecuador and Perú. This makes them some of the oldest known species of freshwater fish. Arapaima is exploited in many ways by local human populations. Its tongue is thought to have medicinal qualities in South America. It is dried and combined with guarana bark, which
720-488: 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
760-663: 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
800-983: 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] Arapaima 4–5, see text The arapaima , pirarucu , or paiche
840-402: 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,
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#1732771837575880-526: The arapaima needs to surface to breathe air, traditional arapaima fishermen harpoon them and then club them to death. An individual fish can yield as much as 70 kg (150 lb) of meat. The arapaima was introduced for fishing in Thailand and Malaysia . Fishing in Thailand can be done in several lakes, where specimens over 150 kg (330 lb) are often landed and then released. On 14 May 2020,
920-608: The arapaima population in the Amazon River Basin is unknown, hence it is listed on the IUCN red list as data deficient . Conducting a population census in so large an area is difficult, as is monitoring catches in a trade that was once largely unregulated . Since 1999, both subsistence and commercial fishing have been permitted in specially designated areas under a sophisticated sustainable management strategy. This approach has led to massive recovery of once-depleted stocks; in
960-463: 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
1000-440: 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 the proximal or basal skeletal elements, the radials, which represent the articulation between these fins and
1040-585: The depths of the Amazon Basin harbors. Sites such as these offer the likelihood of diversity. Arapaima can reach lengths more than 2 m (6 ft 7 in), in some exceptional cases even exceeding 2.6 m (8 ft 6 in) and over 100 kg (220 lb). The maximum recorded weight for the species is 200 kg (440 lb), while the longest recorded length verified was 3.07 m (10 ft 1 in). Anecdotal reports suggest that specimens as long as 4.57 m (15 ft 0 in) exist, but verification
1080-706: 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
1120-412: The fish to remain mobile while heavily armored. The arapaima has a fundamental dependence on surface air to breathe. In addition to gills, it has a modified and enlarged swim bladder , composed of lung -like tissue, which enables it to extract oxygen from the air. The diet of the arapaima consists of fish, crustaceans , fruits, seeds, insects, and small land animals that walk near the shore. The fish
1160-432: 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,
1200-524: The height of commercial arapaima fishing; demand led to farming of the fish by native ribeirinhos . As efforts at restricting catches were largely unsuccessful, arapaima fishing was banned outright in Brazil in 1996, due to declining populations. Indeed, a 2014 study found that the fish were depleted or overexploited at 93% of the sites examined and well-managed or unfished in only 7%; the fish appeared to be extirpated in 19% of these sites. The status of
1240-549: 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
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1280-438: 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
1320-425: 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 the deep sea to subterranean waters to
1360-707: The locals call it, was claimed to be responsible for the mysterious drowning of two men on 17 June. In August 2018, India Times reported that arapaima has been spotted in the Chalakudy River , following floods in Kerala ; their presence in India is attributed to illegal importation for fish farming . The arapaima is depicted on both the flag and the seal of the Department of Ucayali , Peru . Wild arapaima are harpooned or caught in large nets. Since
1400-513: The low-water season, when the lakes are isolated from the rivers and oxygen levels drop, rendering its prey lethargic and vulnerable. Arapaima may leap out of the water if they feel constrained by their environment or harassed. Due to its geographic ranges , arapaima's lifecycle is greatly affected by seasonal flooding . Various pictures show slightly different coloring owing to colour changes when they reproduce. The arapaima lays its eggs when water levels are low or beginning to rise. They build
1440-466: 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
1480-488: The male and the young by circling them and fending off potential predators. In his book, Three Singles to Adventure , naturalist Gerald Durrell reported that in British Guyana , female arapaima had been seen secreting a white substance from a gland in the head, and that their young were seemingly feeding on the substance. Some 23-million-year-old fossils of arapaima or a very similar species have been found in
1520-479: The native range (within South America and elsewhere), where they are sometimes considered invasive species . In Kerala , India, arapaima escaped from aquaculture ponds after floods in 2018 . Its Portuguese name, pirarucu , derives from the Tupi language words pira and urucum , meaning "red fish". Arapaima was traditionally regarded as a monotypic genus , but later, several species were distinguished. As
1560-813: The water for trophy shots can rupture this vessel, causing death. In 2013, Whole Foods began selling farm-raised arapaima in the United States as a cheaper alternative to halibut or Chilean sea bass . In Thailand, the only legal breeding farm is located in Tambon Phrong Maduea, Amphoe Mueang Nakhon Pathom , Nakhon Pathom Province . This has been approved by both the Department of Fisheries and CITES since early 2018, and has been exporting them worldwide as an aquarium fish. Arapaima are particularly vulnerable to overfishing because of their size and because they must surface periodically to breathe. Some 7000 tons per year were taken from 1918 to 1924,
1600-461: Was lost during World War II bombings) and A. mapae from the type specimen. FishBase recognizes four species in the genus. In addition to these, evidence suggests that a fifth species, A. arapaima , should be recognized (this being the widespread, well-known species, otherwise included in A. gigas ). These fish are widely dispersed and do not migrate, which leads scientists to suppose that more species are waiting to be discovered in
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