Roper, Clyde F. E. Division of Molluscs, Smithsonian Institution, U.S. National Museum, Washington, DC.
- Other features
- Links to Primary Literature
- Additional Readings
An order of the class Cephalopoda (subclass Coleoidea, superorder Decapodiformes) commonly known as squids. The true squids arose in the early Mesozoic Period (Permian/Triassic) and have proliferated from the Jurassic to the Recent (Holocene). They are now represented by well over 300 species of living forms (see illustration). Two main groups, the Myopsida and the Oegopsida, are included in the Teuthoidea (also known as Teuthida), and they occur in various marine habitats of the world. Characteristics include 10 circumoral (surrounding the mouth) appendages (eight arms and two tentacles); suckers with chitinous rings or hooks; a buccal membrane (lips); an internal, simple, rod- or featherlike chitinous shell (pen or gladius); and eyes that are covered by a transparent membrane with a minute pore (myopsids) or eyes without any membrane, completely open to the sea (oegopsids). The teuthoids inhabit virtually all marine and estuarine habitats of the world, from surface waters to abyssal depths of 5000 m (16,400 ft) or more. They are foundation members of many ecosystems, as both prey and predator. Currently, in aggregate, more than 4.22 million metric tons (4.65 million tons) of squid are harvested annually in the worldwide squid fisheries. See also: Cephalopoda; Coleoidea; Deep-sea fauna; Marine ecology
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information