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.

Large-tooth flounders
Citharichthys sordidus.jpg
Pacific sanddab, Citharichthys sordidus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Pleuronectiformes
Suborder: Pleuronectoidei
Family: Paralichthyidae
Chabanaud, 1937
Type genus
Girard, 1858


Bigeye flounder, Hippoglossina macrops

They are found in temperate and tropical waters of the Atlantic, Indian and Pacific Oceans.[3]

Dusky flounder, Syacium papillosum

Several species are important commercial and game fishes, notably the California halibut, Paralichthys californicus and the Pacific sanddab, Citharichthys sordidus.

Phylogenetic analyses have long indicated the non-monophyly of this family e.g.,[4] 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 [5]). 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.[5] Molecular phylogenetic evidence indicates that Paralichthyidae in this sense is sister to Pleuronectidae and Cyclopsettidae is sister to Bothidae e.g.[6]


  1. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2012). "Paralichthyidae" in FishBase. October 2012 version.
  2. ^ Kells, V.; and Carpenter, K. (2011). A Field Guide to Coastal Fishes from Maine to Texas. ISBN 978-0-8018-9838-9
  3. ^ "Paralichthyidae" World Register of Marine Species. Retrieved 2014-1-26.
  4. ^ Pardo, Belén G.; Machordom, Annie; Foresti, Fausto; Porto-Foresti, Fábio; Azevedo, Marisa F. C.; Bañon, Rafael; Sánchez, Laura; Martínez, Paulino (2005-12-30). "Phylogenetic analysis of flatfish (Order Pleuronectiformes) based on mitochondrial 16s rDNA sequences". Scientia Marina. 69 (4): 531–543. doi:10.3989/scimar.2005.69n4531. ISSN 1886-8134.
  5. ^ a b Campbell, Matthew A.; Chanet, Bruno; Chen, Jhen‐Nien; Lee, Mao‐Ying; Chen, Wei‐Jen (September 2019). "Origins and relationships of the Pleuronectoidei: Molecular and morphological analysis of living and fossil taxa". Zoologica Scripta. 48 (5): 640–656. doi:10.1111/zsc.12372. ISSN 0300-3256.
  6. ^ Berendzen, Peter B.; Dimmick, Walter Wheaton (August 2002). McEachran, J. D. (ed.). "Phylogenetic Relationships of Pleuronectiformes Based on Molecular Evidence". Copeia. 2002 (3): 642–652. doi:10.1643/0045-8511(2002)002[0642:PROPBO]2.0.CO;2. ISSN 0045-8511.