Flatfish - definition of flatfish by The Free Dictionary Flatfish - definition of flatfish by The Free Dictionary (flăt′fĭsh′) n. pl. flatfish or flat·fish·es Any of numerous chiefly marine fishes of the order Pleuronectiformes, including the flounders, soles, and halibuts, having a laterally compressed body with both eyes on the upper side. flatfish (ˈflætˌfɪʃ) n, pl -fish or -fishes (Animals) any marine spiny-finned fish of the order Heterosomata, including the halibut, plaice, turbot, and sole, all of which (when adult) swim along the sea floor on one side of the body, which is highly compressed and has both eyes on the uppermost side flat•fish (ˈflætˌfɪʃ) n., pl. (esp. collectively) -fish, (esp. for kinds or species) -fish•es. any of various bottom-dwelling fishes of the order Pleuronectiformes that have a flattened, laterally oriented body with both eyes on the upper side.

[1700–10] flat·fish (flăt′fĭsh′) Any of numerous bottom-dwelling fish, such as the flounder, halibut, and sole, that have a flattened body. During a flatfish's larval stage, the head twists and one eye migrates to the other side, so that both eyes in the adult are on one side of the body.

ThesaurusAntonymsRelated WordsSynonymsLegend: Heterosomata , order Heterosomata , order Pleuronectiformes - flatfishes: halibut; sole; flounder; plaice; turbot; tonguefishes flounder - any of various European and non-European marine flatfish righteye flounder , righteyed flounder - flounders with both eyes on the right side of the head holibut , halibut - marine food fish of the northern Atlantic or northern Pacific; the largest flatfish and one of the largest teleost fishes lefteye flounder , lefteyed flounder - flatfishes with both eyes on the left side of the head tonguefish , tongue-fish - left-eyed marine flatfish whose tail tapers to a point; of little commercial value sole - right-eyed flatfish; many are valued as food; most common in warm seas especially European Translations The Skinny on Flatfish - Coastal Living Food » Seafood » The Skinny on Flatfish The Skinny on Flatfish Mild flavor and fine texture make halibut, flounder, and sole some of the most versatile fish in the sea.

By John Shields Email The pedestrian moniker "flatfish" belies this marine order's delicate fillets and divine flavor. Native to U.S. and European coasts, these bottom dwellers-including halibut, flounder, and sole-have a distinctive appearance. As small fry, they resemble most other fish. But as they age into adulthood, one eye migrates to join its mate on the other side, and their bodies flatten. This allows them to burrow into shallow sand and watch for prey and predators above. The various species and the confusing array of locally bestowed names makes shopping for specific flatfish challenging. Luckily, the different varieties of flounder easily substitute for one another, and flounder and halibut are interchangeable in recipes calling for fillets-fortunate, since it's nearly impossible to tell them apart once cut. If given a choice, simply select the freshest. Steve Parkes of Whole Foods' Pigeon Cove Seafood in Gloucester, Massachusetts, says, "Shop with your eyes. Look for bright skin colors, a clarity and opaqueness." Halibut Its Latin name (Hippoglossus) conveys the halibut's size, with some catches weighing in at nearly half a ton.

Not many folks want to go after one with a rod and reel. It's easier to visit a fishmonger. Halibut features firm, white, mild-flavored flesh. As an extra benefit for the health-conscious, it's very low in fat. Of the two main varieties, Atlantic halibut is fished "ostly from north Atlantic waters off the New England coast. The more abundant Pacific halibut dwells from Northern California to the Bering Sea, though the bulk of commercial fishing occurs in Alaska and British Columbia. Sold fresh or frozen, both typæs usually appear as steaks; fillets are a second choice. Die-hard devotees enjoy halibut cheeks (small delicacies from inside the cheek) sautéed, or smoked and used as cocktail appetizers. Flounder An amazing variety of fish hail from the flounder clan: winter flounder, sand dab, witch flounder (which Steve calls "the Cadillac of flounders with the most delicate flavor"), English sole, fluke, plaice, and widely sold yellowtail flounder (aka yellowtail dab or rusty flounder). No matter the type, mild-flavored flounder offers great versatility when it comes to cooking.

Try it baked, broiled, steamed, poached, sautÈed, or even lightly fried. It marries well with a wide range of sauces, including classic lemon butter, aöoli, hollandaise, Creole-style sauces, and simple tomato- or fruit-based salsas. Markets mostly sell flounder as fillets, but they will usually provide whole fish to those who order it ahead. Sole Though several flounder family members have been mislabeled as sole in the United States, no actual sole inhabits American coastal waters. True sole lives on the other side of the Atlantic, from Scandinavia to the Mediterranean, with the best known being Dover sole. Most real sole purchased here arrives frozen, which does not do justice to this fish's delicate texture. A better-albeit pricier-method for enjoying an unadulterated fillet of sole would be to book a flight to a favorite European dining spot. Around The Web BBC - Food - Flatfish recipes Flatfish recipes Pan-fried dab with lemon and mint potatoes By Simon Rimmer Flatfish are also classed as white fish because the main concentration of oils in flatfish species is found in the liver.

They have lean, textured flesh, and each species has a unique flavour. Flatfish are highly popular and include many species that are found globally. Members of the flatfish family include plaice, lemon sole, dab, flounder, Dover sole, halibut, turbot and brill. Skates and rays also come under the heading of flatfish, and they too have lean, white flesh. These fish are classified as cartilaginous, which means they have a soft frame make-up rather than bones. The most sustainable varieties of flatfish are dab and farmed Atlantic halibut. Recipes using flatfish See all recipes using flatfish Buyer's guide The flesh of flatfish should be in a fairly rigid state or feel firm to the touch. Any sticky, gelatinous liquid on the fish should be clear and not congealing. As these fish lose their condition they will become soft and their covering becomes sticky and discoloured. It is widely considered that flatfish taste best once past the state of rigor mortis: the flavour improves after a short period in the fridge. The majority of flatfish are caught in the wild, but the premium fish of high value, such as halibut and turbot, are successfully farmed.

A very small proportion of Dover sole is also farmed. In the wild, flatfish have a dark upper side and pearlescent white underside, while the skin of farmed flatfish can vary in tone and colour. The white side can be mottled with dark markings too and the liquid covering on these fish can be discoloured. Preparation The flavours of individual flatfish match different cooking methods, but as a general rule grilling, pan-frying, baking and deep-frying all work well with these fish. Article by CJ Jackson Commercial Fishing Methods | Britishseafishing.co.uk Commercial Fishing Methods Commercial Fishing Methods There are a wide range of methods used to catch fish commercially – some of the small scale methods of catching fish are relatively low-impact on the environment and do not catch a large amount of fish, whereas large scale commercial fishing can catch massive amounts of fish while also wreaking havoc on the marine environment. Below the main methods of both large and small scale commercial fishing are described. Pelagic Trawling: This type of trawling involves dragging a net through the middle of the water column to catch fish that feed there. In waters around Britain and Ireland this is most likely to be mackerel and herring.

Pelagic trawling does not actually cause much damage to the environment as the nets are not dragging along the seabed. However, this type of trawling can catch huge amounts of fish. Atlantic Dawn , the biggest trawler in the world, can catch 400 tons of pelagic fish every 24-hours, and species such as jack mackerel have been fished down to a fraction of their former abundance in South American and Australian waters due to intensive pelagic trawling. Bottom trawling is a method of trawling which drags a net along the seabed in order to catch fish that live and feed there. Bottom trawling is sometimes referred to as demersal trawling as the nets are dragged through the demersal zone of the sea which is the area on and just above the seabed. The majority of commercially important species such as cod, haddock, plaice, sole and whiting are all caught by bottom trawling. There are several types of bottom trawling. Otter Trawling: This is the most common type of trawling. A boat drags a net along the seabed.

The net is held open by large steel boards (called otter boards – hence the name) which slide apart once the boat begins to move and hold the net open wide. A system of wheels and floats can also be used to hold the mouth of the net open. The net moves through the sea fast enough to force fish that are in its path into the back section of the net (known as the cod end) and the force of water flowing into the net prevents them from swimming out of the net and escaping. The size of the mesh dictates which fish can pass through the net and avoid capture, with a larger mesh size to allow small species with no commercial value and immature fish a chance of avoiding capture. An otter trawl does not scoop up fish as such. Instead, fish are either attracted or disoriented by the net dragging along the seabed and then find themselves caught in the mouth of the net. The fish will try to swim away but eventually find itself exhausted and end up falling back into the cod end of the net. Beam Trawling: A beam trawler is a type of trawler which lowers two separate nets to the seabed from derricks on the side of the boat.

Each net is held open by a solid metal beam which can be up 16 metres across. ‘Tickler chains’ are used to lash the seabed and get flatfish out of the sediment so they can be scooped up by the net. Beam trawls are typically used to catch flatfish commercially, particularly lemon sole, Dover sole and plaice as these species are most likely to bury themselves underneath sand and sediment. However, beam trawls with heavier gear and chains can be used to fish rockier and rougher ground. Beam trawls can leave tracks up to 10cm deep in the seabed and kill a huge range of species such as starfish, crabs, and brittle stars. While these species may be commercially unimportant the knock on effect of removing them from the food chain can be devastating. It is estimated that for every 1lb of marketable fish caught by a beam trawler, 16lb of marine life has been killed. Pulse Trawling: Pulse trawling is an adaptation of beam trawling which fires an electrical pulse through the nets which shocks and stuns fish out of the seabed and allows them to be scooped into the nets.

Dutch trawlers have experimented with pulse trawling but it has yet to gain major acceptance in commercial fishing. Fishermen claim it is less damaging than a traditional beam trawl, but there have been horror stories about masses of dead fish and devastation to the marine environment caused by pulse trawling. It also offers significant fuel savings to trawler owners which may be the real reason they are so keen to push forward with this technology. There is a longer article going into greater depth about the details of pulse trawling and the environmental damage some claim this method of fishing causes available here . Pair Trawling: As the name implies pair trawling involved two vessels dragging one bet between them. The nets used in pair trawling can be massive. Pair trawlers fishing for mackerel in the open sea can drag a net which is 1.6 kilometres long with a mouth opening measuring 60 by 120 metres. To put this into perspective a net this big would be able to fit ten 747 Boeing jumbo jets inside of it. Pair trawling has many advantages.

Fuel costs are lower, the net can be towed faster allowing more ground to be covered and the two vessels can catch and store much more fish working together than they would individually. Pair trawling for bass is banned in UK territorial waters due to the large cetacean (dolphin, whale and marine mammal) bycatch which is caused by this type of fishing. Purse Seining: Purse seining is a method of fishing which is used to catch pelagic fish that are found in a shoal or school such as herring, mackerel, sardines and many species of tuna. Purse seining works by drawing a vast net around a school of fish. The net is then pursed (drawn closed at the bottom) trapping the fish inside and the net can then be pulled onto the vessel. Small-scale purse seining can be relatively low-impact as the seabed is not damaged, however, large-scale purse seining can be devastating. The biggest purse seines can use a net thousands of metres long which goes to a depth of 250 metres and use a speedboat to quickly draw the net around the fish.

These kind of nets can catch up to 400 tons of small species such as jack mackerel, or a whole school of tuna. There is also massive bycatch associated with purse seining for tuna, with dolphins, whales, sharks and turtles inadvertently caught in the net and then thrown back into the sea dead once they have been brought onboard. Dredging: Dredging is used to take shellfish such as oysters, mussels and scallops from the sea. Dredgers tow metal cages across shellfish beds. Metal beams or teeth are used to scrape the shellfish free from the seabed when they then fall back into the cage or into a net or bag attached to the cage. Hydraulic dredgers also exist which spray jets of water onto the shellfish to dislodge them from their location. Large vessels can drag as many as twenty cages behind them. Dredging is one of the most destructive methods of commercial fishing as it tears through shellfish beds and causing major damage. Shellfish beds that have been intensively dredged are unlikely to ever recover from the damage that has been caused to them.

Other Types of Commercial Fishing A black-browed albatross (listed by the IUCN as Near Threatened) caught on a commercial longline. Long-lining: Long-lining is a method of commercial fishing used to catch a range of species. Small scale inshore long-lines can be used to catch mackerel in a way that causes very little damage to the marine environment. However, large-scale long-lining is used to catch species such as marlin, tuna and swordfish. These vessels can unreel up to thirty miles of heavy line from the back of a ship. Thousands of hook snoods – baited by hand with small live fish – are attached to this line which is left at sea for a day and then retrieved, along with any fish that have taken the baits. Although long-lining does not damage the seabed in the way that trawling does it is still harmful to the environment as turtles, sharks and rare marine birds are all inadvertently caught by long-lines across the world, while long-lines that float on or near the surface also catch rare and endangered sea birds such as albatross. An employee of America’s FWS (Fish and Wildlife Service) checks a gill net as part of a research project.

Gill Nets, Drift Nets and Tangle Nets: These type of nets hang in the sea like a wall and catch fish that swim into them. Gill nets are so called because fish get caught by the gills, while tangle nets unsurprisingly see the fish become tangled in the netting. Drift nets are similar to gill nets but are suspended from a boat and allowed to move and drift in the tide. While small scale gill nets can be used responsibly by inshore fishermen (especially when the mesh size is large enough to allow immature fish to swim through) large scale drift nets can be massively damaging due to huge bycatch. Large scale gill nets (longer than 2.5 kilometres across) have been banned by EU fishing vessels since 1992. Gill, tangle and drift nets which have been lost or abandoned by commercial fishing vessels continue to catch fish – potentially for years – and are known as ghost nets . Lobster and crab pots stacked up in Brixham harbour. Lobster and Crab Pots: Lobster and crab pots (also known as traps) are cages made out of metal or wood and rope.

Their design lets crabs and lobsters enter the pot to take the bait but they cannot then get out. They are baited with dead fish and lowered to the seabed on ropes, usually about a dozen at a time. A buoy is used to mark the location and fishermen will return to retrieve their catch after a day or two. This is a responsible form of commercial fishing as there is next to no bycatch – only the target species are taken, and even if fish enter the pot they usually survive and can be returned to the sea. Small, immature and berried (egg carrying) crabs and lobsters can also be returned to the sea.

Share this page: The evolutionary origin of flatfish asymmetry : Article : Nature Nature 454, 209-212 (10 July 2008) | doi :10.1038/nature07108; Received 8 February 2008; Accepted 22 May 2008 The evolutionary origin of flatfish asymmetry Committee on Evolutionary Biology, University of Chicago, 1025 East 57th Street, Chicago, Illinois 60637, USA Department of Geology, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605, USA Correspondence to: Matt Friedman 1 , 2 Correspondence and requests for materials should be addressed to M.F. (Email: mattf@uchicago.edu ). Top of page Abstract All adult flatfishes (Pleuronectiformes), including the gastronomically familiar plaice, sole, turbot and halibut, have highly asymmetrical skulls, with both eyes placed on one side of the head.

This arrangement, one of the most extraordinary anatomical specializations among vertebrates, arises through migration of one eye during late larval development. Although the transformation of symmetrical larvae into asymmetrical juveniles is well documented 1, 2, 3, 4, 5, 6, 7 , the evolutionary origins of flatfish asymmetry are uncertain 1, 2 because there are no transitional forms linking flatfishes with their symmetrical relatives 8, 9 . The supposed inviability of such intermediates gave pleuronectiforms a prominent role in evolutionary debates 10, 11, 12, 13, 14, 15, 16 , leading to attacks on natural selection 11 and arguments for saltatory change 14, 15 . Here I show that Amphistium and the new genus Heteronectes, both extinct spiny-finned fishes from the Eocene epoch of Europe, are the most primitive pleuronectiforms known. The orbital region of the skull in both taxa is strongly asymmetrical, as in living flatfishes, but these genera retain many primitive characters unknown in extant forms.

Most remarkably, orbital migration was incomplete in Amphistium and Heteronectes, with eyes remaining on opposite sides of the head in post-metamorphic individuals. This condition is intermediate between that in living pleuronectiforms and the arrangement found in other fishes. Amphistium and Heteronectes indicate that the evolution of the profound cranial asymmetry of extant flatfishes was gradual in nature. Teleostei Müller, 1846 Pleuronectiformes Bleeker, 1859 Heteronecteschaneti gen. et sp. nov. Etymology. The generic name references a disused collective name for flatfishes (Heterosomata), as well as the incomplete orbital migration characterizing this taxon (Greek heteros, different; nectri, swimmer). The specific name honours B. Chanet and his contributions to the study of fossil pleuronectiforms 8, 9, 17 . Holotype. NHMW 1974.1639.24 + 1974.1639.25 (part and counterpart), Naturhistorisches Museum, Vienna (NHMW).

Total length is 142 mm; standard length is 111 mm. Horizon and locality. Bolca, possibly Monte Postale locality, northern Italy. Lower Eocene (Ypresian; SBZ11) 18 . Diagnosis. Stem pleuronectiform differing from Amphistium in the following characters: the dorsal- and anal-fin spines are robust, being much broader anteroposteriorly than rays in each fin (rather than a similar thickness); the ventral margin of the anal fin is concave (rather than convex; possible autapomorphy); the anal fin comprises three spines and no fewer than 32 soft, bifurcating rays (rather than 22–21). The most notable feature of Heteronectes is its high degree of cranial asymmetry, manifested primarily in the orbital region of the braincase. This pattern does not arise from taphonomic distortion. There is neither torsion-induced damage between the orbital region and the posterior of the braincase nor deformation of other components of the skull ( Fig. 1a, b ).

High resolution image and legend (533K) Download Power Point slide (915K) Slides may be downloaded for educational use, according to the terms described in Nature Publishing Group's licensing policy . As in living flatfishes 2, 19 , the frontal bones of Heteronectes are unequal in size and shape. The right-side frontal bone is broad, rectangular and ventrally extensive, whereas the left-side frontal bone is reduced to a narrow, curved splint that defines the upper margin of the migrated orbit. The orbital margin fails to extend beyond the dorsal midline. This differs from the arrangement in all living adult flatfishes, in which the migrating eye passes completely over the top of the head to a position on the opposite side of the skull ( Fig. 2c ). Thus, whereas Heteronectes shares a displaced orbit with pleuronectiforms, this genus shows a remarkable intermediate condition in which the eyes remain on opposite sides of the head. High resolution image and legend (334K) Download Power Point slide (719K) Slides may be downloaded for educational use, according to the terms described in Nature Publishing Group's licensing policy .

Heteronectes closely resembles Amphistium, another percomorph also known from Bolca (A. paradoxum) 9, 20 and younger (Lutetian) deposits of France (Paris Basin; A. altum) 21 . Amphistium has been allied with numerous acanthomorph groups 9 , although many authors noted—and dismissed—a resemblance to pleuronectiforms. The most recent examination of Amphistium rejected similarities shared by this genus and flatfishes as primitive or homoplastic, but could not determine its relationships within Percomorpha 9 . Although their systematic interpretations diverged, all previous accounts of Amphistium agreed that this genus has a symmetrical skull. Renewed study, using conventional techniques and computed tomography, unequivocally shows that Amphistium is characterized by conspicuous cranial asymmetry centred in the orbital region ( Figs 1c–f and 2b ). Just as in Heteronectes, the migrated orbit of Amphistium does not extend beyond the dorsal midline.

The mode and degree of asymmetry is identical between multiple specimens of Amphistium, clearly demonstrating that it reflects a genuine anatomical pattern rather than post-mortem deformation. Many lines of evidence indicate that the observed cranial morphology in these Eocene fossils represents the adult condition, not an ontogenetic stage preceding complete orbital migration characteristic of all other flatfishes. First, all individuals of Amphistium and Heteronectes are an order of magnitude longer than the size at which eye migration begins in most living flatfishes (between 10 mm and 15 mm) 3 . There is no indication that primitive flatfishes might have metamorphosed at larger body sizes, because the eye passes over the dorsal midline at 13 mm in the anatomically conservative Psettodes 22 . Second, unlike living flatfishes in even the late stages of eye migration 4, 5, 7 , Amphistium and Heteronectes have completely mineralized skulls, with all component ossifications present.

Third, the consistent morphology of all Amphistium specimens—which show identical degrees of asymmetry despite ranging in size between 103 mm (MNHN 10878b/Bol87) and 200 mm (BMNH P.16138) in standard length—indicates this is the adult arrangement. Amphistium and Heteronectes share with flatfishes the specialization of displaced orbits, an unambiguous synapomorphy of that clade 19 . Several other derived features, unrelated to asymmetry, link Amphistium to flatfishes. These characters, which cannot be checked in the incomplete material of Heteronectes, include an anteriorly extensive first dorsal fin, a procumbent first pterygiophore of the dorsal fin, and anteriorly curved neural spines in the abdominal region. However, apart from these flatfish synapomorphies, Amphistium and Heteronectes display a series of generalized percomorph characters lost or transformed in other pleuronectiforms.

These genera retain a single supraneural (uncertain in Heteronectes; absent in crown-group pleuronectiforms), lack a pseudomesial bar (a neomorph that frames the migrated orbit in crown-group pleuronectiforms 6 ), and possess a generalized 'perciform' caudal endoskeleton 23 comprising a full complement of uroneurals, epurals and independent hypurals. Amphistium and Heteronectes also bear fin spines in both the anal and dorsal fins. This diagnostic acanthomorph feature 24, 25 is only found in the plesiomorphic Psettodes among living flatfishes 2, 19 . In the context of a phylogenetic analysis, this distribution of characters indicates that Amphistium and Heteronectes branch from pleuronectiform stem, outside the crown clade that contains living forms plus all other known fossil examples ( Fig. 2a ).

Placement of Heteronectes and Amphistium as successive taxa along the flatfish stem is notable because it suggests that the observed asymmetry in these genera represents an evolutionary intermediate between generalized conditions and the arrangement found in crown-group pleuronectiforms, rather than a secondary development of incomplete orbital migration from an ancestor showing complete transit. Specimens of Amphistium include both dextral and sinistral morphs ( Figs 1c–f and 2b ). This is consistent with the pattern seen in the morphologically primitive living flatfish Psettodes, where the two morphs occur in near equal frequency, but differs from the condition in more derived forms, which typically occur almost exclusively as one morph or the other 26 . Amphistium indicates that indiscriminate orbital migration is primitive for flatfishes, with dominant left- or right-eyed migration representing a derived arrangement. This conforms to a general pattern in the evolution of directional asymmetries that arise late in development, in which groups often first pass through an antisymmetric stage where individuals occur as both dextral and sinistral forms at near-equal frequencies 27 .

Amphistium and Heteronectes deliver the first clear picture of flatfish origins, a hotly contested issue in debates on the mode and tempo of evolution owing to the unclear adaptive value of incomplete eye migration. Flatfishes formed a cornerstone of early arguments against natural selection 11 , forcing Darwin 12 to respond with a scenario that invoked the inheritance of acquired traits, similar to Lamarck's theory of flatfish origins espoused 60 years earlier 10 . Goldschmidt asserted that the first flatfish must have arisen suddenly as a "hopeful monster", bypassing any intermediate forms, and gave this group a key position in his arguments for saltatory evolution 14, 15 . The discovery of stem flatfishes with incomplete orbital migration refutes these claims and demonstrates that the assembly of the flatfish bodyplan occurred in a gradual, stepwise fashion. Thus, the evolutionary origin of flatfish asymmetry resembles its developmental origin, with increasing degrees of orbital migration transforming a symmetrical precursor into a fully asymmetrical form ( Fig. 2c ). Questions about the possible selective advantage of incomplete orbital transit arise from the discovery of stem flatfishes.

Clues are given by living taxa, which often prop their bodies above the substrate by depressing their dorsal- and anal-fin rays 28 . Similar behaviour might have permitted Amphistium and Heteronectes—both of which have long median-fin rays—the use of both eyes while on the sea floor. The unusual morphology and resting orientation of pleuronectiforms have been interpreted as adaptations for prey ambush 16 , and it is clear that stem flatfishes, like morphologically primitive living forms, were piscivorous; one specimen of Amphistium (MCSNV V.D.91+92) contains the remains of a fish nearly half its own length. The fossil record rejects the intuitive notion that incomplete orbital migration might be maladaptive. Stem flatfishes with this condition range over two geological stages and derive from localities that also yield crown pleuronectiforms with full cranial asymmetry 8, 9 . Amphistium and Heteronectes are contemporaries of the earliest members of many derived pleuronectiform lineages 8, 29 , including the oldest known sole 17 .

The sudden appearance of anatomically modern pleuronectiform groups in the Palaeogene period matches the pattern repeated by many acanthomorph clades 24, 29 . Inferring interrelationships between higher groups in this explosive radiation has proved difficult, and an unresolved bush persists 30 . Documenting the origin of these clades is vital to understanding the roots of modern biodiversity, because acanthomorph fishes comprise nearly one-third of living vertebrate species 30 . Stem representatives—such as Amphistium and Heteronectes in the case of pleuronectiforms—have yet to be identified for many acanthomorph clades 24, 29 , but their recognition might prove invaluable in delivering a stable hypothesis of interrelationships for this exceptional vertebrate radiation. Top of page References Kyle, H. M. The asymmetry, metamorphosis, and origin of flat-fishes. Phil. Trans. R. Soc. Lond. B 211, 75–129 (1923) | Article | Norman, J. R. A Systematic Monograph of the Flatfishes (Heterosomata). Vol. 1.

Psettotidae, Bothidae, Pleuronectidae (British Museum (Natural History), London, 1934) Ahlstrom, E. H., Amaoka, K., Hensley, D. A., Moser, H. G. & Sumida, B. Y. in Ontogeny and Systematics of Fishes (eds Moser, H. G. et al.) 640–670 (Allen, Lawrence, Kansas, 1984) Okada, N., Takagi, Y., Seikai, T., Tanaka, M. & Tagawa, M. Asymmetrical development of bones and soft tissues during eye migration of metamorphosing Japanese flounder, Paralichthys olivaceus. Cell Tissue Res. 304, 59–66 (2001) | Article | PubMed | ChemPort | Wagemans, F. & Vandewalle, P. Development of the bony skull in common sole: brief survey of morpho-functional aspects of ossification sequence. J. Fish Biol.

59, 1350–1369 (2001) | Article | Hoshino, K. Fixing the confused term "pseudomesial bar" and homologies of pleuronectiform cranial elements, with proposals of new terms. Ichthyol. Res. 53, 435–440 (2006) | Article | Schreiber, A. M. Asymmetric craniofacial remodeling and lateralized behavior in larval flatfish. J. Exp. Biol. 209, 610–621 (2006) | Article | PubMed | Chanet, B. A cladistic reappraisal of the fossil flatfishes record consequences on the phylogeny of the Pleuronectiformes (Osteichthyes: Teleostei). Ann. Sci. Nat. Zool. 18, 105–117 (1997) Chanet, B. Supposed and true flatfishes [Teleostei: Pleuronectiformes] from the Eocene of Monte Bolca, Italy. Stud. Ric. Giacim. Terz.

Bolca 8, 220–243 (1999) Lamarck, J. B. Philosophie Zoologique (Dentu, Paris, 1809) Mivart, G. J. On the Genesis of Species (MacMillan, London, 1871) Darwin, C. On the Origin of Species by Means of Natural Selection 6th edn (Murray, London, 1872) Wallace, A. R. Darwinism (MacMillan and Co., London, 1889) Goldschmidt, R. Some aspects of evolution. Science 78, 539–547 (1933) | Article | PubMed | Goldschmidt, R. The Material Basis of Evolution (Yale Univ. Press, New Haven, 1940) von Wahlert, G. The role of ecological factors in the origin of higher levels of organization. Syst. Zool. 14, 288–300 (1965) | Article | PubMed | ChemPort | Chanet, B.

Eubuglossus eocenicus (Woodward 1910) from the Upper Lutetian of Egypt, one of the oldest soleids (Teleostei, Pleuronectiformes). Neues Jahrb. Geol. Paläntol. Monatsh. 1994, 391–398 (1994) Trevisani, E., Papazzoni, C. A., Ragazzi, E. & Roghi, G. Early Eocene amber from the "Pesciara di Bolca" (Lessini Mountains, Northern Italy). Palaeogeogr. Palaeoclimatol. Palaeoecol. 223, 260–274 (2005) | Article | Chapleau, F. Pleuronectiform relationships: a cladistic reassessment. Bull. Mar. Sci. 52, 516–540 (1993) Blot, J. Les poissons fossiles du Monte Bolca.

Classés jusqu'ici dans les familles des Carangidae, Menidae, Ephippidae, Scatophagidae. Mem. Mus. Civ. Stor. Nat. Verona 1, 1–525 (1969) Gaudant, J. Sur un Amphistium (poisson téléostéen, Percoidei) de l'Éocène Parisien. Bull. Inf. Géol. Bass. Paris 16, 11–14 (1979) Liew, H.-C., Milward, N. E. & Hartwick, R. F. Descriptions of larval fishes of the genera Psettodes (Psettotidae) and Pseuorhombus (Paralichthyidae) from the Great Barrier Reef, Australia. Aust. J. Mar. Freshwat. Res. 39, 51–70 (1988) | Article | Gosline, W. A. The perciform caudal skeleton.

Copeia 1961, 265–270 (1961) | Article | Patterson, C. An overview of the early fossil record of acanthomorphs. Bull. Mar. Sci. 52, 29–59 (1993) Johnson, G. D. & Patterson, C. Percomorph phylogeny: a survey of acanthomorphs and a new proposal. Bull. Mar. Sci. 52, 554–626 (1993) Hubbs, C. L. & Hubbs, L. C. Bilateral asymmetry and bilateral variation in fishes. Pap. Mich. Acad. Sci. Arts Lett. 30, 229–310 (1944) Palmer, A. R. From symmetry to asymmetry: phylogenetic patterns of asymmetry variation in animals and their evolutionary significance. Proc. Natl Acad. Sci. USA 93, 14279–14286 (1996) | Article | PubMed | ChemPort | Stickney, R. R., White, D.

B. & Miller, D. Observations of fin use in relation to feeding and resting behavior in flatfishes (Pleuronectiformes). Copeia 1973, 154–156 (1973) | Article | Patterson, C. in The Fossil Record 2 (ed. Benton, M. J.) 621–656 (Chapman & Hall, London, 1993) Stiassny, M. L. J., Wiley, E. O., Johnson, G. D. & de Carvalho, M. R. in Assembling the Tree of Life (eds Cracraft, J. & Donoghue, M. J.) 410–429 (Oxford Univ. Press, New York, 2004) Top of page Acknowledgements I thank G. Clément, P. Forey, D. Goujet, M. Richter, O. Schultz, A. Vaccari and M. Véran for loaning or providing access to fossil specimens; R. Arrindell, B. Brown, D. Johnson, S.

Raredon, M. Rogers and M. Westneat for arranging the loan or study of recent material; E. Hilton for checking gill-arch characters in carangids; M. Colbert and A. Gosselin-Ildari for compiling the computed tomography renderings, K. Claeson for providing specimen transport; L. Herzog, A. Shinya, D. Wagner and J. Holstein for helping in fossil preparation; and A. Bannikov, M. Coates, M. LaBarbera and N. Smith for discussion. This work was supported by a grant from the Lerner-Grey Fund for Marine Research, a Hinds Fund Grant, an Evolving Earth Grant, a National Science Foundation Graduate Research Fellowship (award number DGE-0228235), and an Environmental Protection Agency STAR Fellowship (award number FP916730). MORE ARTICLES LIKE THIS These links to content published by NPG are automatically generated. NEWS AND VIEWS

Question: What is the main commercial flatfish in Europe?
Answer: Plaice