Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.
The Characiformes form part of a series called the Otophysi within the superorder Ostariophysi. The Otophysi contain three other orders, Cypriniformes, Siluriformes, and Gymnotiformes.The Characiformes form a group known as the Characiphysi with the Siluriformes and Gymnotiformes. The order Characiformes is the sister group to the orders Siluriformes and Gymnotiformes, though this has been debated in light of recent molecular evidence.
Originally, the characins were all grouped within a single family, the Characidae. Since then, 18 different families have been separated out. However, classification varies somewhat, and the most recent (2011) study confirms the circumscribed Characidae as monophyletic.Currently, 18 families, about 270 genera, and at least 1674 species are known. The suborder Citharinoidei, which contains the families Distichodontidae and Citharinidae, is considered the sister group to the rest of the characins, suborder Characoidei.
The oldest characiform is Santanichthys of the early Cretaceous (Albian stage) of Brazil. While all extant species are of fresh water, this species was probably either brackish or marine. Many other fossils are also known.The Characiformes likely first diversified during the Cretaceous period, though fossils are poorly known. During the Cretaceous period, the rift between South America and Africa would be forming; this may explain the contrast in diversity between the two continents. Their low diversity in Africa may explain why some primitive fish families and the Cypriniformes coexist with them while they are absent in South America, where these fish may have been driven extinct. The characiforms had not spread into Africa soon enough to also reach the land bridge between Africa and Asia. The earliest they could have spread into Central America was the late Miocene.
Phylogeny of living Characiformes based on Betancur-Rodriguez et al. 2017:and Nelson, Grande & Wilson 2016.
Characins possess a Weberian apparatus, a series of bony parts connecting the swim bladder and inner ear.Superficially, the Characiformes somewhat resemble their relatives of the order Cypriniformes, but have a small, fleshy adipose fin between the dorsal fin and tail. Most species have teeth within the mouth, since they are often carnivorous. The body is almost always covered in well-defined scales. The mouth is also usually not truly protractile.
The largest characins are Hydrocynus goliath and Salminus franciscanus , 1.3 m (4.3 ft). The smallest in size is about 1.7 cm (0.67 in) in the Bolivian pygmy blue characin, Xenurobrycon polyancistrus . Many members are under 3 cm (1.2 in).both of which are up to
Characins are most diverse in the Neotropics, where they are found in lakes and rivers throughout most of South and Central America. The red-bellied piranha, a member of the family Serrasalmidae within the Characiformes, is endemic to the Neotropic ecozone. At least 209 species of characins are found in Africa, including the distichodontids, citharinids, alestiids, and hepsetids. The rest of the characins originate from the Americas.
A few characins become quite large, and are important as food or game.Most, however, are small shoaling fish. Many species known as tetras are popular in aquaria due to their bright colors, general hardiness, and tolerance towards other fish in community tanks.
Characidae, the characids or characins is a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their status as a by and large monophyletic group at family rank. To arrive there, this family has undergone much systematic and taxonomic change. Among those fishes that remain in the Characidae for the time being are the tetras, comprising the very similar genera Hemigrammus and Hyphessobrycon, as well as a few related forms such as the cave and neon tetras. Fish of this family are important as food and also include popular aquarium fish species.
Cypriniformes is an order of ray-finned fish, including the carps, minnows, loaches, and relatives. This order contains 11 or 12 families, over 400 genera, and more than 4,250 species, with new species being described every few months or so, and new genera being recognized frequently. They are most diverse in southeastern Asia, and are entirely absent from Australia and South America. At 112 years old, the longest-lived cypriniform fish documented is the bigmouth buffalo.
The Gymnotiformes are a group of teleost bony fishes commonly known as the Neotropical or South American knifefish. They have long bodies and swim using undulations of their elongated anal fin. Found almost exclusively in fresh water, these mostly nocturnal fish are capable of producing electric fields for navigation, communication, and, in the case of the electric eel, attack and defense. A few species are familiar to the aquarium trade, such as the black ghost knifefish, the glass knifefish, and the banded knifefish.
Neopterygii are a group of fish. Neopterygii means "new fins". Only a few changes occurred during their evolution from the earlier actinopterygians. They appeared sometime in the Late Permian, before the time of the dinosaurs. The Neopterygii were a very successful group of fish, because they could move more rapidly than their ancestors. Their scales and skeletons began to lighten during their evolution, and their jaws became more powerful and efficient. While electroreception and the ampullae of Lorenzini are present in all other groups of fish, with the exception of hagfish, Neopterygii have lost this sense, even if it has later been re-evolved within Gymnotiformes and catfishes, which possess nonhomologous teleost ampullae.
The Anostomidae are a family of ray-finned fishes that belong to the order Characiformes. Closely related to the Chilodontidae and formerly included with them, the Anostomidae contain about 150 described species. Commonly known as anostomids, they are found in freshwater habitats from the Río Atrato in northernmost South America to warm-temperate central Argentina; they are of Amazon origin, with few found west of the Andes. Their scientific name approximately means "mouth on top", from Ancient Greek áno- (ἄνω) "up" + stóma (στόμᾶ) "mouth", in reference to the arrangement of these fishes' mouth opening.
Hyphessobrycon is a genus of freshwater fish in the family Characidae. These species are among the fishes known as tetras. The genus is distributed in the Neotropic ecozone from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about six species are from Central America and a single species, H. compressus is from southern Mexico.
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains 10,758 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all continents except Antarctica. They have a number of common characteristics such as an alarm substance and a Weberian apparatus. Members of this group include fish important to people for food, sport, the aquarium industry, and research.
Salminus brasiliensis is a large, predatory characiform freshwater fish found in central and east-central South America. Despite having Salminus in its name, the dorado is not related to any species of salmon, nor to the saltwater fish also called dorado. It is very popular among recreational anglers and supports large commercial fisheries.
The flame tetra, also known as the red tetra or Rio tetra, is a small freshwater fish of the characin family Characidae. This tetra was first introduced as aquarium fish in 1920 by C. Bruening, Hamburg, Germany, and formally described in 1924 by Dr. George S. Myers. Today large numbers are bred in captivity and it is common in the aquarium trade, but the remaining wild population in Southeast Brazil is highly threatened.
Santanichthys diasii is a species of extinct fish that existed around 115 million years ago during the Albian age. S. diasii is regarded as the basal-most characiform, and is the earliest known member of Otophysi. It appears as a small fish, similar in appearance to a modern-day herring little more than 30 millimeters in length. Its most striking characteristic is the presence of a Weberian apparatus, which makes it the most primitive known member of the order Characiformes, the order in which modern-day tetras are classified. Santanichthys has been unearthed from numerous locations throughout Brazil, in rocks dating to the Cretaceous Period. Its presence in these strata is seen as an indicator for the biogeography and evolution of its order.
Salminus, popularly known as dorado or dourado, is a genus of relatively large, predatory freshwater fish from the family Characidae. They are native to large tropical and subtropical rivers in South America, and undertake migrations during the rainy season to spawn. They are very popular among recreational anglers and also support important commercial fisheries.
Acrobrycon is a genus of characin found in tropical South America.
Agoniates is genus of characiform fishes from tropical South America.
Clupeacharax anchoveoides is a species of characiform fish found in Argentina, Bolivia, Brazil, Ecuador and Peru. It is the only member of its genus.
Engraulisoma taeniatum is a species of characiform fish that is found in Argentina, Brazil, Ecuador and Peru. it is found in the basins of the Paraguay and Napo Rivers. Is the sole member of its genus.
Lignobrycon myersi is a species of characiform fish endemic to Brazil where it occurs in the Rio do Braço system. It is the only member of its genus.
Triportheus is a genus of characiform fishes from South America, including Trinidad, ranging from the Rio de la Plata basin to the basins of the Orinoco and Magdalena. Some are migratory.
Triporthidae is a family of characiform fishes, including about 23 species. This family was raised from the status of a subfamily to family based on extensive analysis of characiform species.
The Otocephala is a clade of bony fishes within the Teleostei that evolved some 230 million years ago. It is named for the presence of a hearing (otophysic) link from the swimbladder to the inner ear. Other names proposed for the group include Ostarioclupeomorpha and Otomorpha. The clade contains the Clupeiformes (herrings) and the Ostariophysi, a group of other orders including the Cypriniformes, Gymnotiformes (knifefish), and Siluriformes (catfish). The Otocephala may also contain the Alepocephaliformes (slickheads), but as yet (2016) without morphological evidence. The clade is sister to the Euteleostei which contains the majority of bony fish alive today. In 2015, Benton and colleagues set a "plausible minimum" date for the origin of the crown Otocephala as about 228.4 million years ago. They argued that since the oldest locality for any diversity of stem teleosts is the Carnian of Polberg bei Lunz, Austria, whose base is 235 million years old, a rough estimate for the Otocephala can be made.
Tarumania is a genus of freshwater fish first described in 2017. It contains a single species, Tarumania walkerae, and constitutes the only genus in the family Tarumaniidae. T. walkerae is a predatory species that hunts among the leaf litter of the flooded forest floor in the Rio Negro drainage basin.
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