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 ...
of
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. Tele ...
fishes with spiny
rays. 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
Rosen is a surname of Ashkenazi Jewish origin, the name deriving from the German word for roses. Notable people with this surname include:
People A–H
* Adam Rosen (born 1984), American-born British luger Olympian
* Al Rosen (1924–2015), Amer ...
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
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 sa ...
s, calcium carbonate structures that form the ears of fishes, have been found from the
Jurassic
The Jurassic ( ) is a geologic period and 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 Jurassic constitutes the middle period of ...
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 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''
*''
Congorhynchus''
*''
Blochius''
*''
Enniskillenus''
*''
Homorhynchus
''Homorhynchus'' (Greek for "same snout") is a genus of prehistoric fish from the Eocene and Oligocene.
It was described by Edouard Van Beneden
Édouard Joseph Louis Marie Van Beneden (5 March 1846 in Leuven – 28 April 1910 in Liège), son ...
''
*''
Omosomopsis''
*''
Palaeorhynchus''
*''
Pharmacichthys''
*''
Pseudotetrapterus''
Timeline of genera
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from: -145.5 till: -99.6 color:earlycretaceous text: Early
from: -99.6 till: -66 color:latecretaceous text:Late
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
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
from: -23.03 till: -2.588 color:neogene text: Neogene
from: -2.588 till: 0 color:quaternary text: Q.
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color:latecretaceous bar:NAM1 from:-99.6 till:-93.5 text: Omosomopsis
color:latecretaceous bar:NAM2 from:-95.5 till:-93.5 text: Pharmacichthys
color:latecretaceous bar:NAM3 from:-95.5 till:-33.9 text: Cylindracanthus
color:latecretaceous bar:NAM4 from:-70.6 till:-48.6 text: Congorhynchus
color:eocene bar:NAM5 from:-55.8 till:-48.6 text: Enniskillenus
color:eocene bar:NAM6 from:-55.8 till:-33.9 text: Blochius
color:eocene bar:NAM7 from:-55.8 till:-33.9 text: Asineops
color:eocene bar:NAM8 from:-48.6 till:-28.4 text:Homorhynchus
''Homorhynchus'' (Greek for "same snout") is a genus of prehistoric fish from the Eocene and Oligocene.
It was described by Edouard Van Beneden
Édouard Joseph Louis Marie Van Beneden (5 March 1846 in Leuven – 28 April 1910 in Liège), son ...
color:eocene bar:NAM9 from:-48.6 till:-15.97 text: Palaeorhynchus
color:oligocene bar:NAM10 from:-33.9 till:-23.03 text: Pseudotetrapterus
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from: -145.5 till: -99.6 color:earlycretaceous text: Early
from: -99.6 till: -66 color:latecretaceous text:Late
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
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:era
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
from: -23.03 till: -2.588 color:neogene text: Neogene
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