Large-tooth flounders or sand flounders are a family, Paralichthyidae, of
flounder
Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuaries.
Taxonomy
The name "flounder" is used for several only distantly related species, tho ...
s.
The family contains 14
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 ...
with a total of about 110 species. They lie on the sea bed on their right side; both eyes are always on the left side of the head, while the
Pleuronectidae
Pleuronectidae, also known as righteye flounders, are a family of flounders. They are called "righteye flounders" because most species lie on the sea bottom on their left sides, with both eyes on their right sides. The Paralichthyidae are the opp ...
usually (but not always) have their eyes on the right side of the head.

They are found in
temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
and
tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
waters of the
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe an ...
,
Indian
Indian or Indians may refer to:
Peoples South Asia
* Indian people, people of Indian nationality, or people who have an Indian ancestor
** Non-resident Indian, a citizen of India who has temporarily emigrated to another country
* South Asia ...
and
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
s.
Several species are important commercial and
game fish
Game fish, sport fish or quarry refer to popular fish pursued by recreational anglers, and can be freshwater or saltwater fish. Game fish can be eaten after being caught, or released after capture. Some game fish are also targeted commercia ...
es, notably the
California halibut
The California halibut or California flounder (''Paralichthys californicus'') is a large-tooth flounder native to the waters of the Pacific Coast of North America from the Quillayute River in Washington to Magdalena Bay in Baja California. It ...
, ''Paralichthys californicus'' and the
Pacific sanddab, ''Citharichthys sordidus''.
Phylogenetic analyses have long indicated the non-monophyly of this family e.g., and two lineages have been consistently apparent. Termed groups, the two groups were named after genera: a ''Cyclopsetta'' group and a ''Pseudorhombus'' group (see summary in
). A formal description of Cycopsettidae in 2019 created this family consisting of four genera: ''Cyclopsetta'', ''Etropus'', ''Citharichthys'', and ''Syacium'' corresponding to the previously recognized ''Cyclopsetta'' group.
Molecular phylogenetic evidence indicates that Paralichthyidae in this sense is sister to Pleuronectidae and Cyclopsettidae is sister to Bothidae e.g.
References
{{Taxonbar, from=Q1156541
Taxa named by Paul Chabanaud
Marine fish families