The true soles are a family, Soleidae, of

flatfish A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating ...

es. It includes saltwater and

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estua ...

water species in the East Atlantic, Indian Ocean, and West and Central Pacific Ocean. Freshwater species are found in Africa, southern Asia,

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torres ...

, and Australia. In the past, soles of the Americas (both fresh and salt water) were included in this family, but they have been separated to their own family, the

American sole The American soles are a family (Achiridae) of flatfish occurring in both freshwater and marine environments of the Americas. The family includes about 35 species in seven genera. These are closely related to the soles (Soleidae), and have be ...

s (Achiridae). The only true sole remaining in that region is ''

Aseraggodes herrei ''Aseraggodes'' is a genus of soles native to the Indian and Pacific oceans. These small flatfishes are poisonous. Species It is by far the most species rich genus in the family Soleidae, as there currently are 54 recognized species: * ''Asera ...

'' of the Galápagos and

Cocos Island Cocos Island ( es, Isla del Coco) is an island in the Pacific Ocean administered by Costa Rica, approximately southwest of the Costa Rican mainland. It constitutes the 11th of the 13 districts of Puntarenas Canton of the Province of Puntare ...

. The true soles are bottom-dwelling fishes feeding on small

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 other

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. The family contains 30

genera 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 family. In binomial nomenclat ...

and a total of about 180 species. Soles begin life as

bilaterally symmetric Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pl ...

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e, with an eye on each side of the head, but during development, the left eye moves around onto the right side of the head. Adult soles lie on their left (blind) sides on the

sea floor 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 ...

, often covered in mud, which in combination with their dark colours, makes them hard to spot. A flatfish resembling a small halibut or sole was observed by the

Bathyscaphe Trieste ''Trieste'' is a Swiss-designed, Italian-built deep-diving research bathyscaphe which reached a record depth of about in the Challenger Deep of the Mariana Trench near Guam in the Pacific. On 23 January 1960, Jacques Piccard (son of the boat ...

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 deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum known ...

at a depth around . This observation has been questioned by fish experts, and recent authorities do not recognize it as valid.Jamieson, A.J., and Yancey, P. H. (2012).
On the Validity of the Trieste Flatfish: Dispelling the Myth.
'

The Biological Bulletin ''The Biological Bulletin'' is a peer-reviewed scientific journal covering the field of biology. The journal was established in 1897 as the ''Zoological Bulletin'' by Charles Otis Whitman and William Morton Wheeler. In 1899 the title was changed to ...

222(3): 171-175 Many soles are important food species: the common sole, ''Solea solea'', is popular in northern

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...

. Image:Aecor_u0.png,

Unicorn sole ''Aesopia cornuta'' is a species of sole native to the Indian and western Pacific Oceans. Its common names include the unicorn sole, thickray sole, banded sole, and dark thick-rayed sole. This species grows to a standard length of , and is the ...

, ''Aesopia cornuta'' Image:Buglossidium luteum.jpg, Solenette, ''Buglossidium luteum'' Image:Solea solea 1.jpg, Common sole, ''Solea solea''

References

{{Taxonbar, from=Q736867 Ray-finned fish families Taxa named by Charles Lucien Bonaparte