IntroductionThe
piranha's are members of the Characidae (or Characin) family, a large family of
more than 1200 species, including some of the most widespread and popular
aquarium fish like the all the common tetra's and hatchetfish. The piranha's
belong to a sub-family called the Serrasalmidae (serra means 'saw', 'sawed' or
'serrated', salmus means 'salmon'), a name based on the fact that all members
have a sharp, serrated keel running over the belly to make the body more
streamlined (for faster swimming). How many members this subfamily consists of
is not certain because there is a lot of debate over the proper scientific
classification. Besides that, new unidentified species, regional varieties and
color forms are discovered, and new and/or updated research data (concerning
DNA, parasites, morphology etc.) is published on a fairly regular basis. For
what is known, there are at least more than 40 different species (Silver
Dollars, Pacu's, Whimple Piranha's etc. included).
TaxonomyPiranhas belong to the subfamily Serrasalminae, which also includes closely related omnivorous[3] fish such as pacus.[4] Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis and Serrasalmus are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be monophyletic, it should be restricted to Serrasalmus, Pygocentrus and part of Pristobrycon, or expanded to include these taxa plus Pygopristis, Catoprion, and Pristobrycon striolatus. Pygopristis was found to be more closely related to Catoprion than the other three piranha genera.[4] The total number of piranha species is unknown and contested, and new species continue to be described. Estimates range from fewer than 30 to more than 60.[4]
Piranha species GENUS PYGOCENTRUS (True Piranha's) Pygocentrus cariba: Cariba Piranha, Cariba, Caribe, Black Shoulder Piranha, Orinoco Piranha, Black Eared Piranha, Venuzuelan Red Belly Piranha Pygocentrus nattereri: Redbellied Piranha, Red Bellied Piranha, Redbelly Piranha, Red, Red Breasted Piranha, Red Piranha, Piranha, Common Piranha, Pygocentrus nattereri 'Ternetzi', Ternetzi Piranha, Yellow King Emperor Piranha, Gold Dust Piranha, Yellow Nattereri, Golden Redbellied Piranha, Yellow Redbellied Piranha Pygocentrus piraya: Piraya, Piraya Piranha, Black-Tailed Piranha, Rio São Francisco Piranha, King Emperor Piranha GENUS SERRASALMUS (Pirambeba's) Serrasalmus altispinis: ??? Serrasalmus altuvei: Altuvei Piranha, "Caribe Azul" Serrasalmus brandtii: Brandtii Piranha, Green Piranha, "Cavaca" Serrasalmus compressus: Compressus Piranha Serrasalmus eigenmanni: Eigenmann's Piranha Serrasalmus elongatus: Elongated Piranha, Pike Piranha, Pingke Piranha, Serrasalmus pinke, "Caribe Pinche" Serrasalmus geryi: Geryi's Piranha, Violet Line Piranha Serrasalmus gibbus: Gibbus Piranha, Castelnau's Piranha, "Caribe Dorado" Serrasalmus gouldingi: Goulding's Piranha Serrasalmus hastatus: ??? Serrasalmus hollandi: Holland's Piranha Serrasalmus humeralis: Humeralis Piranha, Serrasalmus irritans: Iredescent Piranha, "Caribe Pinche" Serrasalmus maculatus: Maculatus Piranha, Mac Serrasalmus manueli: Manuel's Piranha, Green Tiger Piranha, "Caribe Parguasero" Serrasalmus marginatus: "Caribe" Serrasalmus medinai: Medinai Piranha, Red Throat Piranha, "Caribe" Serrasalmus nalseni: "Caribe Pintado" Serrasalmus neveriensis: Rio Neveri Piranha, "Caribe de Rio" Serrasalmus rhombeus: Rhombeus Piranha, Rhom, Black Piranha, White Piranha, Peruvian Black Piranha, Brazilian Black Piranha, Spotted Piranha, S. Niger Piranha, "Caribe Amarillo", "Caribe Ojo Rojo" Serrasalmus sanchezi: Ruby-Red Piranha, Ruby-Throated Diamond Piranha Serrasalmus serrulatus: "Caribe Cortador" Serrasalmus spilopleura: Spilopleura Piranha, Spilo, Gold Piranha, Gold Spilopleura, Ruby Red Piranha, Purple Spilopleura, Black Piranha, Black Diamond Piranha, Speckled Piranha, Black-Banded Piranha, "Caribe Dorado" GENUS PRISTOBRYON Pristobrycon aureus: Gold Piranha, "Palometa", "Palometa de Rio", Yellow Palometa Pristobrycon calmoni: Dusky Piranha Pristobrycon careospinus: ??? Pristobrycon maculipinnis: Gemarmerde Piranha Pristobrycon striolatus: Spotted Piranha, Scapularis Piranha, "Caribito", "Palometa Caribe"
GENUS PYGOPRISTIS Pygopristis denticulata: Five-Cusped Piranha, Denticulata Piranha, Big-Toothed Piranha, Gold Piranha, "Caribe Palometa", "Caribito" GENUS CATOPRION (Wimpel Piranha's) Catoprion mento: Wimpel Piranha PACU'S Colossoma bidens: Black Pacu, Silver Pacu Colossoma brachypomus: Pacu, Common Pacu, Red Pacu Colossoma macropomum: ??? Colossoma oculus: ??? Colossoma orbignyanum: ??? Acnodon normani: Sheep Pacu Acnodon oligacanthus: ??? Ossubtus xinguensi: Parrot Pacu
SILVER DOLLARS Metynnis altidorsalis: ??? Metynnis argenteus: Silver Dollar Metynnis fasciatus: Striped Silver Dollar Metynnis guaporensis: ??? Metynnis hypsauchen: Schreitmüller's Silver Dollar, Striped Silver Dollar Metynnis lippincottianus: Spotted Silver Dollar Metynnis luna: Red-Spot Silver Dollar Metynnis maculatus: Speckled Silver Dollar Metynnis mola: ??? Metynnis otuquensis: ??? Myleus rubripinnis: Red Hook Silver Dollar Myleus schomburgki: Black-Barred Silver Dollar Mylossoma duriventre: Silver Mylossoma, Hard-Bellied Silver Dollar
DistributionPiranhas are found in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paraná, and the São Francisco River systems. Some species of piranha have broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have more limited distributions.[4] Aquarium piranhas have been introduced into parts of the United States, with specimens occasionally found in the Potomac River, Lake of the Ozarks in Missouri and even as far north as Lake Winnebago in Wisconsin, although they typically do not survive cold winters.[5] Piranhas have also been discovered in the Kaptai Lake in southeast Bangladesh. Research is being carried out to establish how piranhas have moved to such distant corners of the world from their original habitat. Some rogue exotic fish traders are thought to have released them in the lake to avoid being caught by antipoaching forces. Piranhas were also spotted in the Lijiang River in China.[6] DescriptionJawbone of Pygocentrus nattereriPiranhas are normally about 14 to 26 cm long (5.5 to 10.25 inches), although some specimens have been reported to be up to 43 cm (17.0 inches) in length.[7] Serrasalmus, Pristobrycon, Pygocentrus and Pygopristis are most easily recognized by their unique dentition. All piranhas have a single row of sharp teeth in both jaws; the teeth are tightly packed and interlocking (via small cusps) and are used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed and blade-like (flat in profile). There is minor variation in the number of cusps; in most species, the teeth are tricuspid with a larger middle cusp which makes the individual teeth appear markedly triangular. The exception is Pygopristis, which has pentacuspid teeth and a middle cusp usually only slightly larger than the other cusps. In the scale-eating Catoprion, the shape of their teeth is markedly different and the premaxillary teeth are in two rows, as in most other serrasalmines.[4] EcologyPiranhas are important ecological components of their native environments. Although largely restricted to lowland drainages, these fish are widespread and inhabit diverse habitats within both lotic and lentic environments. Some piranha species are abundant locally, and multiple species often occur together.[4] As both predators and scavengers, piranhas influence the local distribution and composition of fish assemblages.[4] Certain piranha species consume large quantities of seeds, but unlike the related Colossoma and Piaractus, herbivorous piranhas thoroughly masticate and entirely devour all seeds eaten and consequently do not function as dispersers.[4] Piranha have a reputation as ferocious predators that hunt their prey in schools. Recent research, however, which "started off with the premise that they school as a means of cooperative hunting", discovered that they are timid fish that schooled for protection from their own predators, such as cormorants, caimans, and dolphins. Piranhas are "basically like regular fish with large teeth".[8] Research on the species Serrasalmus aff. brandtii and Pygocentrus nattereri in Viana Lake, which is formed during the wet season when the Rio Pindare (a tributary of the Rio Mearim) floods, has shown that these species eat vegetable matter at some stages in their life; they are not strictly carnivorous fish.[9] Relationship with humansPiranha teeth are often used to make tools and weapons by the indigenous population. Piranhas are also popular as food, although if an individual piranha is caught on a hook or line, it may be attacked by other (free) piranhas.[citation needed] Piranhas are commonly consumed by subsistence fishermen, and often sold for food in local markets.[4] In recent decades, dried specimens have been marketed as tourist souvenirs.[4] Piranhas occasionally bite and sometimes injure bathers and swimmers.[10][11] A piranha bite is considered more an act of carelessness than that of misfortune, but piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.[4] Several piranha species appear in the aquarium trade.[4] Piranhas can be bought as pets in some areas, but they are illegal in many parts of the United States.[12]It is illegal to import piranhas in the Philippines and violators could face six months to four years of jail.[13] Piranhas lay their eggs in little groups and swim around to protect them. Eggs are usually layed in corpses so the young piranhas may feed afterwards right after they had hatched. The most common aquarium piranha is Pygocentrus nattereri, the red-bellied piranha. Piranhas can be bought fully grown or as babies, often no larger than a thumbnail. It is important to keep Pygocentrus piranhas alone or in groups of four or more, not in pairs, since aggression among them is common, not allowing the weaker fish to survive, and is distributed more widely when kept in larger groups. It is not rare to find individuals with one eye missing due to a previous attack. Piranhas are likely to become cannibalistic on others in their group if underfed.[citation needed] Legendary reputationThere are various myths about piranhas such as how they can dilacerate a human body or cattle in seconds. These myths refer specifically to Pygocentrus nattereri, the red-bellied piranha.[14] A recurrent myth is that they can be attracted by blood and are exclusive carnivores.[15] A Brazilian myth called "piranha cattle" states that they sweep the rivers at high speed and attack the first of the cattle entering the water allowing the rest of the group to traverse the river.[16] These myths were dismissed through research by Helder Queiroz and Anne Magurran and published on Biology Letters.[17] Nevertheless, a study in Suriname found that piranhas may occasionally attack humans, particularly when water levels are low.[18] Attacks on humans are usually reported around docks where fish are frequently gutted and entrails are commonly thrown into the water.[citation needed] Theodore RooseveltWhen American President Theodore Roosevelt visited Brazil, Brazilian fishermen set up an incident in which a cow was consumed by piranhas. The locals blocked off part of an Amazon tributary with nets and dumped hordes of starving piranhas into it when the adventure-loving Roosevelt explored the region on a hunting trip. A cow was tossed into the river, setting off a wild feeding frenzy that quickly reduced the carcass to bones—the "instant skeleton" now associated with piranhas.[19][20] Roosevelt would later present the piranhas as vicious creatures in his 1914 book Through the Brazilian Wilderness, indicating that They are the most ferocious fish
in the world. Even the most formidable fish, the sharks or the barracudas,
usually attack things smaller than themselves. But the piranhas habitually
attack things much larger than themselves. They will snap a finger off a hand
incautiously trailed in the water; they mutilate swimmers—in every river town
in Paraguay there are men who have been thus mutilated; they will rend and
devour alive any wounded man or beast; for blood in the water excites them to
madness. They will tear wounded wild fowl to pieces; and bite off the tails of
big fish as they grow exhausted when fighting after being hooked. In popular cultureHollywood would later emblazon the above gory image for posterity and profit. An example of this perception of piranhas in media appears in the 1967 James Bond film You Only Live Twice, where a piece of meat is shown being fed to pet piranhas owned by the film's main antagonist, Blofeld, then only a bone is raised from the water. Later on, a woman is thrown to the piranha pool, although all that is seen is water bubbling vigorously. Piranha (1978) and Piranha II: The Spawning (1981) perpetuated the piranha's sinister image by showing murderous piranha fish biting and eating humans. Piranha 3D (2010) is another Hollywood film, this time portraying the incident as starting with an under-water fault opening and allowing pre-historic piranha into a lake (versus an accidental addition as in the 1978 film).
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