Acanthomorpha (meaning "thorn-shaped") is an extraordinarily diverse

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

teleost Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Tel ...

fishes with spiny

ray Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (g ...

s. The clade contains about one third of the world's modern species of vertebrates: over 14,000 species. A key anatomical innovation in acanthomorphs is hollow and unsegmented spines at the anterior edge of the dorsal and anal fins. A fish can extend these sharp bony spines to protect itself from predators, but can also retract them to decrease drag when swimming. Another shared feature is a particular rostral cartilage, associated with ligaments attached to the rostrum and premaxilla, that enables the fish to protrude its jaws considerably to catch food. Rosen coined the name in 1973 to describe a clade comprising Acanthopterygii, Paracanthopterygii, and also ctenothrissiform fossils from the

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 ...

Period, such as ''Aulolepis'' and ''Ctenothrissa''. Those fossils share several details of the skeleton, and especially of the skull, with modern acanthomorphs. Originally based on anatomy, Acanthomorpha has been borne out by more recent molecular analyses.

Phylogeny

The phylogeny of living

bony fishes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartila ...

Fossil record and evolutionary history

Some

otolith An otolith ( grc-gre, ὠτο-, ' ear + , ', a stone), also called statoconium or otoconium or statolith, is a calcium carbonate structure in the saccule or utricle of the inner ear, specifically in the vestibular system of vertebrates. The s ...

s, calcium carbonate structures that form the ears of fishes, have been found from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Period that may belong to acanthomorphs, but the oldest body fossils from this taxon are only known from the middle of the Cretaceous Period, about 100 million years ago. Acanthomorphs from the early Late Cretaceous were small, typically about 4 centimeters long, and fairly rare. Toward the beginning of the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

era, they exploded in an adaptive radiation, so by the time their fossils begin appear more frequently in Eocene-aged strata, they had reached their modern diversity of 300 families. Recently discovered fish scales from Poland suggest that the oldest acanthomorphs occurred on Late Triassic. Some examples of extinct acanthomorph genera include: e *''

Asineops ''Asineops'' (Greek for "donkey-faced") is a genus of prehistoric fish from the Eocene. It was described by Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anat ...

'' *''

Congorhynchus ''Congorhynchus'' ( Greek for "Congo snout") is an enigmatic, likely polyphyletic genus of prehistoric marine ray-finned fish that was described by E. Darteville and E. Casier in 1949. It is only known from isolated spines that were previously ...

'' *'' Blochius'' *''

Enniskillenus ''Enniskillenus'' (named after the Northern Irish village of Enniskillen) is a genus of prehistoric fish from the Eocene. It was described by Casier in 1966. References ''Enniskillenus'' Paleobiology Database Acanthomorpha Eocene fish E ...

'' *''

Homorhynchus ''Homorhynchus'' (Greek for "same snout") is a genus of prehistoric fish from the Eocene and Oligocene. It was described by Edouard Van Beneden in 1873. References''Homorhynchus''
Paleobiology Database Acanthomorpha Eocene fish Oligoce ...

'' *''

Omosomopsis ''Omosomopsis'' is a genus of prehistoric ray-finned fish from the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this ...

'' *''

Palaeorhynchus ''Palaeorhynchus'' (meaning "old snout") is a genus of prehistoric fish from Central and Southeastern Europe that was described by Wagner in 1860. One fossil found is dated (Early Oligocene The Rupelian is, in the geologic timescale, the ol ...

'' *''

Pharmacichthys ''Pharmacichthys'' is a genus of prehistoric, deep-bodied fish that was described by Woodward in 1942. Species of the genus ''Pharmacichthys'' are known only from Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or ...

'' *''

Pseudotetrapterus ''Pseudotetrapterus'' (Greek for "false four fins") is a genus of prehistoric fish from the Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( t ...

Timeline of genera

ImageSize = width:1500px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-145.5 till:0 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: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. PL, P.L., Pl, or .pl may refer to: Businesses and organizations Government and political * Partit Laburista, a Maltese political party * Liberal Party (Brazil, 2006), a Brazilian political party * Liberal Party (Moldova), a Moldovan political p ...

from: -2.588 till: -0.0117 color:pleistocene text:

from: -0.0117 till: 0 color:holocene text: H. bar:eratop from: -145.5 till: -66 color:cretaceous text:

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 of ...

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:-93.5 text:

color:latecretaceous bar:NAM2 from:-95.5 till:-93.5 text:

color:latecretaceous bar:NAM3 from:-95.5 till:-33.9 text:

Cylindracanthus ''Cylindracanthus'' is an extinct genus of Cretaceous to Eocene 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 (su ...

color:latecretaceous bar:NAM4 from:-70.6 till:-48.6 text:

color:eocene bar:NAM5 from:-55.8 till:-48.6 text:

color:eocene bar:NAM6 from:-55.8 till:-33.9 text: Blochius color:eocene bar:NAM7 from:-55.8 till:-33.9 text:

color:eocene bar:NAM8 from:-48.6 till:-28.4 text:

color:eocene bar:NAM9 from:-48.6 till:-15.97 text:

color:oligocene bar:NAM10 from:-33.9 till:-23.03 text:

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

from: -2.588 till: -0.0117 color:pleistocene text:

from: -0.0117 till: 0 color:holocene text: H. bar:era from: -145.5 till: -66 color:cretaceous 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

Notes Sources * * {{Taxonbar, from=Q337777 Taxa named by Donn Eric Rosen Articles which contain graphical timelines