pleuronectiform

Encyclopedia

pleuronectiform

any member of the order Pleuronectiformes, which includes about 600 species of bony, oval-shaped, flattened fishes such as the flounder, halibut, and turbot. The pleuronectiforms are unique among fishes in being asymmetrical. They are strongly compressed, with both eyes on one side, while other fishes and vertebrates in general are bilaterally symmetrical. The asymmetry is believed to have evolved from a generalized, symmetrical percoid (sea bass) body pattern in a fish that habitually rested on its side. Larval flatfishes have an eye on each side of the head, but during a period of rapid body change (metamorphosis) one eye migrates to the other side of the head, after which the larvae settle to the bottom. Osteological changes resulting from the eye migration are responsible for the asymmetry in the flatfish skull.

Learn more about pleuronectiform with a free trial on Britannica.com.

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source
Explore Dictionary.com
Previous Definition: pleuronectidae
Next Definition: pleuronectoid
Words Near: pleuronectiform
More from Thesaurus.com
Synonyms and Antonyms for pleuronectiform
More from Reference.com
Search for articles containing pleuronectiform
More from Dictionary.com Translator
Dictionary.com Word FAQs

Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.

Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature