The Tetraodontiformes are an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

of highly derived

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

, also called the Plectognathi. Sometimes these are classified as a

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

of the order

Perciformes Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means ...

. The Tetraodontiformes are represented by 10 extant families and at least 349

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

overall; most are marine and dwell in and around tropical

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...

s, but a few species are found in freshwater streams and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

. They have no close relatives, and descend from a line of

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and se ...

-dwelling species that emerged around 80 million years ago.

Description

Various bizarre forms are included here, all radical departures from the streamlined body plan typical of most fishes. These forms range from nearly square or triangular (

boxfish Ostraciidae is a family of squared, bony fish belonging to the order Tetraodontiformes, closely related to the pufferfishes and filefishes. Fish in the family are known variously as boxfishes, cofferfishes, cowfishes and trunkfishes. It contains ...

es), globose (

pufferfish Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowies, bubblefish, globefish, swellfis ...

es) to laterally compressed (

filefish The filefish (Monacanthidae) are a diverse family of tropical to subtropical tetraodontiform marine fish, which are also known as foolfish, leatherjackets or shingles. They live in the Atlantic, Pacific and Indian Oceans. Filefish are closely r ...

es and

triggerfish Triggerfish are about 40 species of often brightly colored fish of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacif ...

es). They range in size from ''

Rudarius excelsus ''Rudarius'' is a genus of filefish The filefish (Monacanthidae) are a diverse family of tropical to subtropical tetraodontiform marine fish, which are also known as foolfish, leatherjackets or shingles. They live in the Atlantic, Pacific and ...

'' (a filefish), measuring just in length, to the

ocean sunfish The ocean sunfish or common mola (''Mola mola'') is one of the largest bony fish in the world. It was misidentified as the heaviest bony fish, which was actually a different species, '' Mola alexandrini''. Adults typically weigh between . The sp ...

, the largest of all bony fishes at up to in length and weighing over 2 tonnes. Most members of this order – except for the family Balistidae – are ostraciiform swimmers, meaning the body is rigid and incapable of lateral flexure. Because of this, they are slow-moving and rely on their pectoral, dorsal, anal, and caudal fins for propulsion rather than body undulation. However, movement is usually quite precise; dorsal and anal fins aid in manoeuvring and stabilizing. In most species, all fins are simple, small, and rounded, except for the pelvic fins which, if present, are fused and buried. Again, in most members, the gill plates are covered over with skin, the only gill opening a small slit above the pectoral fin. The tetraodontiform strategy seems to be defense at the expense of speed, with all species fortified with scales modified into strong plates or spines – or with tough, leathery skin (the filefishes and ocean sunfish). Another striking defensive attribute found in the

es and porcupinefishes is the ability to inflate their bodies to greatly increase their normal diameter; this is accomplished by sucking water into a

diverticulum In medicine or biology, a diverticulum is an outpouching of a hollow (or a fluid-filled) structure in the body. Depending upon which layers of the structure are involved, diverticula are described as being either true or false. In medicine, t ...

of the

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

. Many species of the

Tetraodontidae Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowies, bubblefish, globefish, swellfis ...

, Triodontidae, and Diodontidae are further protected from predation by

tetrodotoxin Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovere ...

, a powerful

neurotoxin Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nerv ...

concentrated in the animals' internal organs. Tetraodontiforms have highly modified

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

s, with no

nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery * ...

, parietal, infraorbital, or (usually) lower

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

bones. The bones of the jaw are modified and fused into a sort of "

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for fo ...

"; visible sutures divide the beaks into "

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, ...

". This is alluded to in their name, derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

words ' meaning "four" and ' meaning "tooth" and the

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

''forma'' meaning "shape". Counting these teeth-like bones is a way of distinguishing similar families, for example, the Tetraodontidae ("four-toothed"), Triodontidae ("three-toothed"), and Diodontidae ("two-toothed"). Their jaws are aided by powerful muscles, and many species also have

pharyngeal teeth Pharyngeal teeth are teeth in the pharyngeal arch of the throat of cyprinids, suckers, and a number of other fish species otherwise lacking teeth.invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

s, such as

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapoda, decapods, ostracoda, seed shrimp, branchiopoda, branchiopods, argulidae, fish lice, krill, remipedes, isopoda, isopods, barnacles, copepods, ...

s and

shellfish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environ ...

. The

Molidae The Molidae comprise the family of the molas or ocean sunfishes, unusual fish whose bodies come to an end just behind the dorsal and anal fins, giving them a "half-fish" appearance. They are also the largest of the ray-finned bony fish, with the ...

are conspicuous even within this oddball order; they lack

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth wit ...

s and spines, and are propelled by their very tall dorsal and anal fins. The caudal peduncle is absent and the caudal fin is reduced to a stiff rudder-like structure. Molids are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

rather than reef-associated and feed on soft-bodied invertebrates, especially

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbre ...

Families

This cladogram of extant Tetraodontiformes is based on Santini et al., 2013.

Fossil families

* Superfamily †Plectocretacicoidea Tyler & Sorbini, 1996 ** †

Cretatriacanthidae ''Cretatriacanthidae'' is an extinct family of prehistoric ray-finned fish. Genera *'' Cretatriacanthus'' Tyler & Sorbini, 1996 *'' Slovenitriacanthus'' Tyler & Križnar, 2013 References Tetraodontiformes Prehistoric ray-finned fish fami ...

Tyler & Sorbini, 1996 ** † Plectocretacicidae Tyler & Sorbini, 1996 ** † Protriacanthidae Tyler & Sorbini, 1996 * † Bolcabalistidae (e.g.

Eospinus ''Eospinus daniltshenkoi'' is an extinct tetraodontid bony fish from the Eocene. Its fossils are from the Danata Formation lagerstatten of Ypresian Turkmenistan. ''E. daniltshenkoi'' had four dorsal spines, three of which were on the anter ...

) Santini & Tyler, 2003 * † Eoplectidae * † Moclaybalistidae Santini & Tyler, 2003 * †

Spinacanthidae Spinacanthidae is an extinct prehistoric family of tetraodontid bony fish that lived from the Lutetian epoch of Eocene Monte Bolca. In life, either genus would have resembled a somewhat-flattened boxfish with five massive spines along the ...

Timeline of genera

ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-145.5 till:15 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-145.5 ScaleMinor = unit:year increment:1 start:-145.5 TimeAxis = orientation:hor AlignBars = justify Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:HER value:teal id:HAD value:green id:OMN value:blue id:black value:black id:white value:white id:cretaceous value:rgb(0.5,0.78,0.31) id:earlycretaceous value:rgb(0.63,0.78,0.65) id:latecretaceous value:rgb(0.74,0.82,0.37) id:cenozoic value:rgb(0.54,0.54,0.258) id:paleogene value:rgb(0.99,0.6,0.32) id:paleocene value:rgb(0.99,0.65,0.37) id:eocene value:rgb(0.99,0.71,0.42) id:oligocene value:rgb(0.99,0.75,0.48) id:neogene value:rgb(0.999999,0.9,0.1) id:miocene value:rgb(0.999999,0.999999,0) id:pliocene value:rgb(0.97,0.98,0.68) id:quaternary value:rgb(0.98,0.98,0.5) id:pleistocene value:rgb(0.999999,0.95,0.68) id:holocene value:rgb(0.999,0.95,0.88) BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:NAM13 bar:NAM14 bar:NAM15 bar:NAM16 bar:NAM17 bar:NAM18 bar:NAM19 bar:NAM20 bar:NAM21 bar:NAM22 bar:NAM23 bar:NAM24 bar:NAM25 bar:NAM26 bar:NAM27 bar:NAM28 bar:NAM29 bar:NAM30 bar:NAM31 bar:NAM32 bar:NAM33 bar:NAM34 bar:NAM35 bar:NAM36 bar:NAM37 bar:NAM38 bar:space bar:period bar:space bar:era PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: -145.5 till: -99.6 color:earlycretaceous text:

Early Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

from: -99.6 till: -66 color:latecretaceous text: Late from: -66 till: -55.8 color:paleocene text: Paleo. from: -55.8 till: -33.9 color:eocene text: Eo. from: -33.9 till: -23.03 color:oligocene text: Oligo. from: -23.03 till: -5.332 color:miocene text: Mio. from: -5.332 till: -2.588 color:pliocene text: Pl. from: -2.588 till: -0.0117 color:pleistocene text: Pl. from: -0.0117 till: 0 color:holocene text: H. bar:eratop from: -145.5 till: -66 color:cretaceous text:

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

from: -66 till: -23.03 color:paleogene text:

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

from: -23.03 till: -2.588 color:neogene text:

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

from: -2.588 till: 0 color:quaternary text: Q. PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left color:latecretaceous bar:NAM1 from:-99.6 till:-97.6 text:

Plectocretacicus ''Plectocretacicus'' is an extinct genus of prehistoric ray-finned fish that lived during the lower Cenomanian. It contains a single species, ''P. clarae''. ''Plectocretacicus'' is the earliest known member of the order Tetraodontiformes. See ...

color:latecretaceous bar:NAM2 from:-74.9 till:-68.9 text:

Cretatriacanthus ''Cretatriacanthus'' is an extinct genus of prehistoric ray-finned fish. It contains a single species, ''C. guidotti''. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may a ...

color:latecretaceous bar:NAM3 from:-70.6 till:-48.6 text:

Kankatodus ''Kankatodus'' is an extinct genus of prehistoric ray-finned fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organiza ...

color:paleocene bar:NAM4 from:-66 till:-55.8 text:

Indotrigonodon ''Indotrigonodon'' is an extinct genus of prehistoric bony fish that lived during the Paleocene epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: P ...

color:paleocene bar:NAM5 from:-66 till:-55.8 text: Pisdurodon color:paleocene bar:NAM6 from:-66 till:-33.9 text:

Eotrigonodon ''Eotrigonodon'' is an extinct genus of prehistoric bony fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations ...

color:eocene bar:NAM7 from:-55.8 till:-48.6 text:

color:eocene bar:NAM8 from:-55.8 till:-33.9 text: Eodiodon color:eocene bar:NAM9 from:-55.8 till:-33.9 text: Eolactoria color:eocene bar:NAM10 from:-55.8 till:-33.9 text: Eoplectus color:eocene bar:NAM11 from:-55.8 till:-33.9 text:

Eotetraodon ''Eotetraodon'' is an extinct genus of prehistoric pufferfish that lived during the Lutetian epoch of middle Eocene. Fossil specimens are from the Monte Bolca lagerstatten (''E. pygmaeus''), and the Kuma Horizon of the Gorny Luch locality, fro ...

color:eocene bar:NAM12 from:-55.8 till:-33.9 text:

Proaracana ''Proaracana dubia'' is an extinct, prehistoric aracanid boxfish that lived during the Lutetian of middle Eocene Monte Bolca. See also * ''Eolactoria'' * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a r ...

color:eocene bar:NAM13 from:-55.8 till:-33.9 text:

Prodiodon ''Prodiodon'' is an extinct genus of prehistoric bony fish that lived from the early to middle Eocene. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: Pe ...

color:eocene bar:NAM14 from:-55.8 till:-33.9 text: Protacanthodes color:eocene bar:NAM15 from:-55.8 till:-33.9 text: Protobalistium color:eocene bar:NAM16 from:-55.8 till:-33.9 text:

Spinacanthus ''Spinacanthus cuneiformis'' is an extinct prehistoric tetraodontid bony fish that lived from the Lutetian epoch of Eocene Monte Bolca. In life, it would have resembled a somewhat-flattened boxfish with five long spines along the anterior- ...

color:eocene bar:NAM17 from:-55.8 till:-33.9 text: Zignoichthys color:eocene bar:NAM18 from:-55.8 till:-33.9 text: Progymnodon color:eocene bar:NAM19 from:-55.8 till:0 text:

Amanses ''Amanses scopas'', also known as the broom filefish, is a filefish, the only species in the genus ''Amanses'' of the family Monacanthidae. It is also called brush-sided leatherjacket in Australia or broom leatherjacket in Christmas Island.Matsu ...

color:eocene bar:NAM20 from:-55.8 till:0 text: Diodon color:eocene bar:NAM21 from:-55.8 till:0 text:

Triodon Triodon may refer to: * Triodon (book), a liturgical book of the Orthodox Church * ''Triodon'' (fish), a genus of fish in the family Triodontidae * ''Triodon'' (plant), a genus of plants now synonymized with ''Diodia'' {{Disambiguation, genus ...

color:eocene bar:NAM22 from:-55.8 till:0 text:

Ostracion ''Ostracion'' is a genus of the boxfish family Ostraciidae. Fish in the genus are known as box puffers. It was first described by Carl Linnaeus in 1758 and makes a brief appearance in Jules Verne's maritime sci-fi novel Twenty Thousand Leagu ...

color:eocene bar:NAM23 from:-48.6 till:0 text:

Triacanthus ''Triacanthus'' is a genus in tripod fish family (Triacanthidae) native to the Indian Ocean and the western Pacific Ocean. Species There are currently 2 recognized species in this genus:Matsuura, K. (2014): Taxonomy and systematics of tetraodont ...

color:oligocene bar:NAM24 from:-33.9 till:-28.4 text:

Acanthopleurus ''Acanthopleurus'' is an extinct genus of prehistoric bony fish that lived during the early Oligocene epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: ...

color:oligocene bar:NAM25 from:-33.9 till:-28.4 text:

Balistomorphus ''Balistomorphus'' is an extinct genus of prehistoric triggerfish that lived a marine environment during the early Oligocene epoch in what is now Canton Glarus, Switzerland. See also * Prehistoric fish * List of prehistoric bony fish A ''l ...

color:oligocene bar:NAM26 from:-33.9 till:-28.4 text:

Cryptobalistes ''Cryptobalistes'' is an extinct genus of prehistoric bony fish that lived during the early Oligocene epoch. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to ...

color:oligocene bar:NAM27 from:-33.9 till:-28.4 text: Oligobalistes color:oligocene bar:NAM28 from:-33.9 till:-28.4 text:

Oligolactoria ''Oligolactoria bubiki'' is an extinct prehistoric boxfish that lived during the Rupelian epoch from the Middle Oligocene of Moravia, Czech Republic. In life, it would have strongly resembled a modern cowfish (genus '' Lactoria''). See als ...

color:oligocene bar:NAM29 from:-33.9 till:-5.332 text:

Oligodiodon ''Oligodiodon'' is an extinct genus of prehistoric ray-finned fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organiz ...

color:oligocene bar:NAM30 from:-28.4 till:0 text:

Aracana ''Aracana'' is a genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below fa ...

color:miocene bar:NAM31 from:-23.03 till:0 text: Marosichthys color:miocene bar:NAM32 from:-15.97 till:-2.588 text:

Trigonodon ''Trigonodon'' is an extinct genus of prehistoric ray-finned fish. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organiz ...

color:miocene bar:NAM33 from:-15.97 till:0 text:

Balistes ''Balistes'' is a genus of triggerfish. Species There are currently four recognized species in this genus:Matsuura, K. (2014): Taxonomy and systematics of tetraodontiform fishes: a review focusing primarily on progress in the period from 1980 to ...

color:miocene bar:NAM34 from:-15.97 till:0 text:

Tetraodon ''Tetraodon'' is a genus in the pufferfish family (Tetraodontidae) found in freshwater in Africa. It is the type genus of the family and historically included numerous other species; several Asian species were only moved to the genera '' Dichotom ...

color:miocene bar:NAM35 from:-11.608 till:0 text:

Chilomycterus ''Chilomycterus'' is a genus of diodontid tetraodontiform fishes commonly called "burrfish." Species There are currently 5 recognized species in this genus:Matsuura, K. (2014): Taxonomy and systematics of tetraodontiform fishes: a review focu ...

color:miocene bar:NAM36 from:-11.608 till:0 text: Mola color:pliocene bar:NAM37 from:-5.332 till:-2.588 text:

Kyrtogymnodon ''Kyrtogymnodon'' is an extinct genus of prehistoric porcupinefish that lived during the Pliocene epoch of Europe. See also * Prehistoric fish * List of prehistoric bony fish A ''list'' is any set of items in a row. List or lists may also ref ...

color:pliocene bar:NAM38 from:-5.332 till:0 text: Alutera PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -145.5 till: -99.6 color:earlycretaceous text:

from: -66 till: -23.03 color:paleogene text:

from: -23.03 till: -2.588 color:neogene text:

from: -2.588 till: 0 color:quaternary text: Q.

References

*
Tree of Life: Tetraodontiformes
* {{Taxonbar, from=Q211837 Extant Cenomanian first appearances