Paralichthyidae

Large-tooth flounders or sand flounders are a family, Paralichthyidae, of flounders.^[1][2] The family contains 14 genera 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 usually (but not always) have their eyes on the right side of the head.^[3]

Large-tooth flounders Temporal range: Miocene–present PreꞒ Ꞓ O S D C P T J K Pg N
Summer flounder (Paralichthys dentatus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Carangiformes
Suborder:	Pleuronectoidei
Family:	Paralichthyidae Regan, 1910
Type genus
Paralichthys Girard, 1858
Genera[1]
See text

They are found in temperate and tropical waters of the Atlantic, Indian and Pacific Oceans.^[4] Several species are important commercial and game fishes, notably the California halibut, Paralichthys californicus.

Taxonomy

The following genera are placed in this family:^[5]

• Ancylopsetta
• Cephalopsetta
• Gastropsetta
• Hippoglossina
• Paralichthys
• Pseudorhombus
• Tarphops
• Tephrinectes
• Thysanopsetta
• Xystreurys

One extinct fossil genus is known in †Evesthes from the Late Miocene of California, USA.^[6]

Bigeye flounder, Hippoglossina macrops

Phylogenetic analyses have long indicated the non-monophyly of this family,^[7] and two lineages have been consistently apparent. Termed groups, the two groups were named after genera: a Cyclopsetta group and a Pseudorhombus group.^[8] The "Cyclopsetta group" was formally described as Cyclopsettidae in 2019, consisting of four genera: Cyclopsetta, Etropus, Citharichthys, and Syacium.^[8] Molecular phylogenetic evidence indicates that Paralichthyidae in this sense is sister to Pleuronectidae and Cyclopsettidae is sister to Bothidae.^[9]