A flatfish is a member of the
ray-finned demersal fish suborder Pleuronectoidei, also called the Heterosomata. In many species, both eyes lie on one side of the head, one or the other migrating through or around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward. The most primitive members of the group, the
threadfins, do not resemble the flatfish but are their closest relatives.
Many important
food fish are in this order, including the
flounders,
soles,
turbot,
plaice, and
halibut. Some flatfish can
camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
themselves on the ocean floor.
Taxonomy
Due to their highly distinctive morphology, flatfishes were previously treated as belonging to their own order, Pleuronectiformes. However, more recent taxonomic studies have found them to group within a diverse group of nektonic marine fishes known as the
Carangiformes
Carangiformes is a large, diverse order of ray-finned fishes within the clade Percomorpha. It is part of a sister clade to the Ovalentaria, alongside its sister group, the Anabantaria (including Anabantiformes and Synbranchiformes). The Cara ...
, which also includes
jacks and
billfish. Specifically, flatfish are most closely related to the
threadfins, which are now also placed in the suborder Pleuronectoidei. Together, the group is most closely related to the
archerfish and
beachsalmons within
Toxotoidei. Due to this, they are now treated as a suborder of the Carangiformes.
Over 800 described species are placed into 16 families.
When they were treated as an order, the flatfishes are divided into two suborders, Psettodoidei and Pleuronectoidei, with > 99% of the species diversity found within the Pleuronectoidei. The largest families are
Soleidae,
Bothidae and
Cynoglossidae with more than 150 species each. There also exist two monotypic families (
Paralichthodidae and
Oncopteridae). Some families are the results of relatively recent splits. For example, the
Achiridae were classified as a subfamily of Soleidae in the past, and the
Samaridae were considered a subfamily of the Pleuronectidae.
[Randall, J. E. (2007). ''Reef and Shore Fishes of the Hawaiian Islands.'' ][Cooper, J.A.; and Chapleau, F. (1998). ''Monophyly and intrarelationships of the family Pleuronectidae (Pleuronectiformes), with a revised classification.'' Fish. Bull. 96 (4): 686–726.] The families
Paralichthodidae,
Poecilopsettidae, and
Rhombosoleidae were also traditionally treated as subfamilies of Pleuronectidae, but are now recognised as families in their own right.
The
Paralichthyidae has long been indicated to be paraphyletic, with the formal description of
Cyclopsettidae in 2019 resulting in the split of this family as well.
The
taxonomy
image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy
Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...
of some groups is in need of a review. The last
monograph
A monograph is generally a long-form work on one (usually scholarly) subject, or one aspect of a subject, typically created by a single author or artist (or, sometimes, by two or more authors). Traditionally it is in written form and published a ...
covering the entire order was
John Roxborough Norman's ''Monograph of the Flatfishes'' published in 1934. In particular, ''
Tephrinectes sinensis'' may represent a family-level lineage and requires further evaluation e.g.
New species are described with some regularity and
undescribed species
In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...
likely remain.
[
]
Hybrids
Hybrids are well known in flatfishes. The Pleuronectidae have the largest number of reported hybrids of marine fishes.[Garrett, D.L.; Pietsch, T.W.; Utter, F.M.; and Hauser, L. (2007). ''The Hybrid Sole Inopsetta ischyra (Teleostei: Pleuronectiformes: Pleuronectidae): Hybrid or Biological Species?'' American Fisheries Society 136: 460–468] Two of the most famous intergeneric hybrids are between the European plaice (''Pleuronectes platessa'') and European flounder (''Platichthys flesus'') in the Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...
, and between the English sole (''Parophrys vetulus'') and starry flounder (''Platichthys stellatus'') in Puget Sound
Puget Sound ( ; ) is a complex estuary, estuarine system of interconnected Marine habitat, marine waterways and basins located on the northwest coast of the U.S. state of Washington (state), Washington. As a part of the Salish Sea, the sound ...
. The offspring of the latter species pair is popularly known as the hybrid sole and was initially believed to be a valid species in its own right.[
]
Distribution
Flatfishes are found in oceans worldwide, ranging from the Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
, through the tropics, to Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
. Species diversity is centered in the Indo-West Pacific and declines following both latitudinal and longitudinal gradients away from the Indo-West Pacific. Most species are found in depths between 0 and , but a few have been recorded from depths in excess of . None have been confirmed from the abyssal or hadal zones. An observation of a flatfish from the Bathyscaphe Trieste at the bottom of the Mariana Trench
The Mariana Trench is an oceanic trench located in the western Pacific Ocean, about east of the Mariana Islands; it is the deep sea, deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maxi ...
at a depth of almost has been questioned by fish experts, and recent authorities do not recognize it as valid. Among the deepwater species, '' Symphurus thermophilus'' lives congregating around "ponds" of sulphur at hydrothermal vents on the seafloor. No other flatfish is known from hydrothermal vents. Many species will enter brackish or fresh water, and a smaller number of soles (families Achiridae and Soleidae) and tonguefish ( Cynoglossidae) are entirely restricted to fresh water.
Characteristics
The most obvious characteristic of the flatfish is its asymmetry
Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as reflection). Symmetry is an important property of both physical and abstract systems and it may be displayed in pre ...
, with both eyes lying on the same side of the head in the adult fish. In some families, the eyes are usually on the right side of the body (dextral or right-eyed flatfish), and in others, they are usually on the left (sinistral or left-eyed flatfish). The primitive spiny turbots include equal numbers of right- and left-sided individuals, and are generally less asymmetrical than the other families.[ Other distinguishing features of the order are the presence of protrusible eyes, another adaptation to living on the ]seabed
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
( benthos), and the extension of the dorsal fin onto the head.
The most basal members of the group, the threadfins, do not closely resemble the flatfishes.
The surface of the fish facing away from the sea floor is pigmented, often serving to camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
the fish, but sometimes with striking coloured patterns. Some flatfishes are also able to change their pigmentation to match the background, in a manner similar to some cephalopods
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
. The side of the body without the eyes, facing the seabed, is usually colourless or very pale.
In general, flatfishes rely on their camouflage for avoiding predators, but some have aposematic traits such as conspicuous eyespots (e.g., '' Microchirus ocellatus'') and several small tropical species (at least '' Aseraggodes'', '' Pardachirus'' and '' Zebrias'') are poisonous.[ Juveniles of '' Soleichthys maculosus'' ]mimic
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. In the simples ...
toxic flatworms of the genus '' Pseudobiceros'' in both colours and swimming mode. Conversely, a few octopus
An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...
species have been reported to mimic flatfishes in colours, shape and swimming mode.
The flounders and spiny turbots eat smaller fish, and have well-developed teeth. They sometimes seek prey in the midwater, away from the bottom, and show fewer extreme adaptations than other families. The soles, by contrast, are almost exclusively bottom-dwellers, and feed on invertebrates. They show a more extreme asymmetry, and may lack teeth on one side of the jaw.[
Flatfishes range in size from '' Tarphops oligolepis'', measuring about in length, and weighing , to the Atlantic halibut, at and .][
]
Species and species groups
* Brill
* Dab
* Sanddab
* Flounder
* Halibut
* Megrim
* Plaice
* Sole
* Tonguefish
* Turbot
Reproduction
Flatfishes lay eggs that hatch into larvae resembling typical, symmetrical, fish. These are initially elongated, but quickly develop into a more rounded form. The larvae typically have protective spines on the head, over the gills, and in the pelvic and pectoral fins. They also possess a swim bladder
The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...
, and do not dwell on the bottom, instead dispersing from their hatching grounds as plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...
.[
The length of the planktonic stage varies between different types of flatfishes, but eventually they begin to metamorphose into the adult form. One of the eyes migrates across the top of the head and onto the other side of the body, leaving the fish blind on one side. The larva also loses its swim bladder and spines, and sinks to the bottom, laying its blind side on the underlying surface.
]
Origin and evolution
Scientists have been proposing since the 1910s that flatfishes evolved from percoid ancestors.[Regan C.T. (1910). "The origin and evolution of the Teleostean fishes of the order Heterosomata". ''Annals and Magazine of Natural History'' 6(35): p. 484-496]
doi.org/10.1080/00222931008692879
/ref> There has been some disagreement whether they are a monophyletic group. Some palaeontologists think that some percomorph groups other than flatfishes were "experimenting" with head asymmetry during the Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
, and certain molecular studies conclude that the primitive family of Psettodidae evolved their flat bodies and asymmetrical head independently of other flatfish groups.[Campbell M.A., Chen W-J. & López J.A. (2013). "Are flatfishes (Pleuronectiformes) monophyletic?". ''Molecular Phylogenetics and Evolution'' 69(3): p. 664-673]
doi.org/10.1016/j.ympev.2013.07.011
/ref>[Campbell M.A., López J.A., Satoh T.P., Chen W-J. & Miya M. (2014). "Mitochondrial genomic investigation of flatfish monophyly". ''Gene'' 551(2): p. 176-182]
doi.org/10.1016/j.gene.2014.08.053
/ref> Many scientists, however, argue that pleuronectiformes are monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria:
# the grouping contains its own most recent co ...
.[Duarte-Ribeiro E, Rosas-Puchuri U, Friedman M, Woodruff G.C., Hughes L.C., Carpenter K.E., White W.T., Pogonoski J.J., Westneat M, Diaz de Astarloa J.M., Williams J.T., Santos M.D., Domínguez-Domínguez O, Ortí G, Arcila D & Betancur-R R. (2024). "Phylogenomic and comparative genomic analyses support a single evolutionary origin of flatfish asymmetry". ''Nature Genetics'' 56: p. 1069-1072]
doi.org/10.1038/s41588-024-01784-w
/ref>
The fossil record indicates that flatfishes might have been present before the Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
, based on fossil otolith
An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle (ear), utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule ...
s resembling those of modern pleuronectiforms dating back to the Thanetian and Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...
stages (57-53 million years ago).[Schwarzhans W. (1999). "A comparative morphological treatise of recent and fossil otoliths of the order Pleuronectiformes". ''Piscium Catalogus. Otolithi Piscium 2''. doi:10.13140/2.1.1725.5043]
Flatfishes have been cited as dramatic examples of evolutionary adaptation. Richard Dawkins
Richard Dawkins (born 26 March 1941) is a British evolutionary biology, evolutionary biologist, zoologist, science communicator and author. He is an Oxford fellow, emeritus fellow of New College, Oxford, and was Simonyi Professor for the Publ ...
, in '' The Blind Watchmaker'', explains the flatfishes' evolutionary history thus:
...bony fish as a rule have a marked tendency to be flattened in a vertical direction.... It was natural, therefore, that when the ancestors of latfishtook to the sea bottom, they should have lain on one ''side''.... But this raised the problem that one eye was always looking down into the sand and was effectively useless. In evolution this problem was solved by the lower eye 'moving' round to the upper side.
The origin of the unusual morphology of flatfishes was enigmatic up to the 2000s, and early researchers suggested that it came about as a result of saltation rather than gradual evolution through natural selection, because a partially migrated eye were considered to have been maladaptive. This started to change in 2008 with a study on the two fossil genera '' Amphistium'' and '' Heteronectes'', dated to about 50 million years ago. These genera retain primitive features not seen in modern types of flatfishes. In addition, their heads are less asymmetric than modern flatfishes, retaining one eye on each side of their heads, although the eye on one side is closer to the top of the head than on the other.[Friedman M. (2008). "The evolutionary origin of flatfish asymmetry". ''Nature'' 454(7201): p. 209–212. doi:10.1038/nature07108] The more recently described fossil genera '' Quasinectes''[Bannikov A.F. & Zorzin R (2019)]
"A new genus and species of ''incertae sedis'' percomorph fish (Perciformes) from the Eocene of Bolca in northern Italy, and a new genus for ''Psettopsis latellai'' Bannikov, 2005"
''Studi e ricerche sui giacimenti terziari di Bolca'': p. 5-15. and '' Anorevus''[Bannikov A.F. & Zorzin R. (2020)]
"A new genus and species of percomorph fish ("stem pleuronectiform") from the Eocene of Bolca in northern Italy"
''Miscellanea Paleontologica'' 17: p. 5–14 have been proposed to show similar morphologies and have also been classified as "stem pleuronectiforms". Suchs findings lead Friedman to conclude that the evolution of flatfish morphology "happened gradually, in a way consistent with evolution via natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
—not suddenly, as researchers once had little choice but to believe."
To explain the survival advantage of a partially migrated eye, it has been proposed that primitive flatfishes like ''Amphistium'' rested with the head propped up above the seafloor (a behaviour sometimes observed in modern flatfishes), enabling them to use their partially migrated eye to see things closer to the seafloor.[Janvier P. (2008). "Squint of the fossil flatfish". ''Nature'' 454(7201): p. 169–170]
While known basal genera like ''Amphistium'' and ''Heteronectes'' support a gradual acquisition of the flatfish morphology, they were probably not direct ancestors to living pleuronectiforms, as fossil evidence indicate that most flatfish lineages living today were present in the Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
and contemporaneous with them. It has been suggested that the more primitive forms were eventually outcompeted.
File:Pleuronectes platessa.jpg, The European plaice is the principal commercial flatfish in Europe.
File:Lined sole.jpg, American soles are found in both freshwater and marine environments of the Americas.
File:Alaska 2007 071.jpg, Halibut are the largest of the flatfishes, and provide lucrative fisheries.
File:Psetta maxima Luc Viatour.jpg, The turbot is a large, left-eyed flatfish found in sandy shallow coastal waters around Europe.
File:Flatfish-lefteyed-flounder.jpg, Flatfish (left‐eyed flounder)
As food
Flatfish is considered a Whitefish because of the high concentration of oils within its liver. Its lean flesh makes for a unique flavor that differs from species to species. Methods of cooking include grilling, pan-frying, baking and deep-frying.
Timeline of genera
ImageSize = width:600px height:auto barincrement:15px
PlotArea = left:10px bottom:50px top:10px right:10px
Period = from:-65.5 till:15
TimeAxis = orientation:horizontal
ScaleMajor = unit:year increment:5 start:-65.5
ScaleMinor = unit:year increment:1 start:-65.5
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:white value:black
id:white value:white
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: -65.5 till: -55.8 color:paleocene text:Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
from: -55.8 till: -33.9 color:eocene text:Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
from: -33.9 till: -23.03 color:oligocene text:Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
from: -23.03 till: -5.332 color:miocene text:Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
from: -5.332 till: -2.588 color:pliocene text: Plio.
from: -2.588 till: -0.0117 color:pleistocene text: Pleist.
from: -0.0117 till: 0 color:holocene text: H.
bar:eratop
from: -65.5 till: -23.03 color:paleogene text:Paleogene
The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...
from: -23.03 till: -2.588 color:neogene text:Neogene
The Neogene ( ,) 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 million years ago. It is the second period of th ...
from: -2.588 till: 0 color:quaternary text: Q.
PlotData=
align:left fontsize:M mark:(line,white) width:5 anchor:till align:left
color:eocene bar:NAM1 from:-55.8 till:-33.9 text: Amphistium
color:eocene bar:NAM2 from:-55.8 till:-33.9 text: Eobothus
color:eocene bar:NAM3 from:-55.8 till:-33.9 text: Eobuglossus
color:eocene bar:NAM4 from:-55.8 till:-33.9 text: Imhoffius
color:eocene bar:NAM5 from:-55.8 till:-33.9 text: Joleaudichthys
color:eocene bar:NAM6 from:-55.8 till:-33.9 text: Turahbuglossus
color:eocene bar:NAM7 from:-55.8 till:0 text: Scophthalmus
color:eocene bar:NAM8 from:-55.8 till:0 text: Citharus
color:eocene bar:NAM9 from:-55.8 till:0 text: Psettodes
color:eocene bar:NAM10 from:-37.2 till:0 text: Arnoglossus
color:oligocene bar:NAM11 from:-33.9 till:0 text: Bothus
color:oligocene bar:NAM12 from:-33.9 till:0 text: Monolene
color:oligocene bar:NAM13 from:-33.9 till:0 text: Solea
color:oligocene bar:NAM14 from:-28.4 till:0 text: Buglossidium
color:oligocene bar:NAM15 from:-28.4 till:0 text: Hippoglossoides
color:oligocene bar:NAM16 from:-28.4 till:0 text: Lepidorhombus
color:miocene bar:NAM17 from:-23.03 till:0 text: Dicologoglossa
color:miocene bar:NAM18 from:-23.03 till:0 text: Paraplagusia
color:miocene bar:NAM19 from:-23.03 till:0 text: Platichthys
color:miocene bar:NAM20 from:-15.97 till:0 text: Achiurus
color:miocene bar:NAM21 from:-15.97 till:0 text: Microchirus
color:miocene bar:NAM22 from:-15.97 till:0 text: Microstomus
color:miocene bar:NAM23 from:-11.608 till:-5.332 text: Evesthes
color:miocene bar:NAM24 from:-11.608 till:0 text: Citharichthys
color:miocene bar:NAM25 from:-11.608 till:0 text:Monochirus
''Monochirus'' is a genus of small soles. It contains two species; one from the northeast Atlantic and Mediterranean, and the second from the South China Sea.
Species
There are currently two recognized species in this genus:
* '' Monochirus hi ...
color:miocene bar:NAM26 from:-11.608 till:0 text: Paralichthys
color:miocene bar:NAM27 from:-11.608 till:0 text: Pleuronichthys
color:pliocene bar:NAM28 from:-5.332 till:0 text: Atheresthes
color:pliocene bar:NAM29 from:-5.332 till:0 text:Clidoderma
''Clidoderma'' is a genus of righteye flounders containing one extant species and two described fossil species from Japan.
Fossil species
Two fossil species are known from the Miocene of Japan. ''Clidoderma chitaensis, C. chitaensis'' Ohe & K ...
color:pliocene bar:NAM30 from:-5.332 till:0 text: Glyptocephalus
color:pliocene bar:NAM31 from:-5.332 till:0 text: Limanda
color:pliocene bar:NAM32 from:-5.332 till:0 text: Lyopsetta
color:pliocene bar:NAM33 from:-5.332 till:0 text: Pegusa
color:pleistocene bar:NAM34 from:-2.588 till:-0.0117 text: Chibapsetta
color:pleistocene bar:NAM35 from:-2.588 till:0 text: Eopsetta
color:pleistocene bar:NAM36 from:-2.588 till:0 text: Isopsetta
color:pleistocene bar:NAM37 from:-2.588 till:0 text: Parophrys
color:pleistocene bar:NAM38 from:-2.588 till:0 text: Symphurus
PlotData=
align:center textcolor:black fontsize:M mark:(line,black) width:25
bar:period
from: -65.5 till: -55.8 color:paleocene text:Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
from: -55.8 till: -33.9 color:eocene text:Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
from: -33.9 till: -23.03 color:oligocene text:Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
from: -23.03 till: -5.332 color:miocene text:Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
from: -5.332 till: -2.588 color:pliocene text: Plio.
from: -2.588 till: -0.0117 color:pleistocene text: Pleist.
from: -0.0117 till: 0 color:holocene text: H.
bar:era
from: -65.5 till: -23.03 color:paleogene text:Paleogene
The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...
from: -23.03 till: -2.588 color:neogene text:Neogene
The Neogene ( ,) 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 million years ago. It is the second period of th ...
from: -2.588 till: 0 color:quaternary text: Q.
See also
* Sinistral and dextral
References
Further reading
*
* Gibson, Robin N (Ed) (2008) Flatfishes: biology and exploitation. Wiley.
* Munroe, Thomas A (2005) "Distributions and biogeography." Flatfishes: Biology and Exploitation: 42–67.
External links
Information on Canadian fisheries of plaice
{{Authority control
Commercial fish
Articles which contain graphical timelines
Extant Paleocene first appearances
Asymmetry