Voight, Janet R. Department of Zoology, Field Museum, Chicago, Illinois.
Roper, Clyde F. E. Division of Molluscs, Smithsonian Institution, U.S. National Museum, Washington, DC.
Ward, Peter D. Department of Geological Sciences, University of Washington, Seattle, Washington.
- General characteristics
- Brain and nervous system
- Eye structure
- Respiration, circulation, and excretion
- Food, feeding, and digestion
- Size, age, and growth
- Fossil record
- Chambered shell
- Evolutionary radiations and extinctions
- Links to Primary Literature
- Additional Readings
A class in the phylum Mollusca that is exclusively marine and contains the extant members—squids, cuttlefishes, octopuses, and the chambered nautiluses—and the fossil taxa—ammonoids, nautiloids, and belemnoids. The earliest known cephalopod fossils date to roughly 500 million years ago from the Upper Cambrian of northeast China. Fossilized external shells of the extinct subclass Ammonoidea and the nearly extinct subclass Nautiloidea are interpreted as indicating that these animals were shallow-living and slow-moving. Despite the thousands of species of such shelled cephalopods that have been recognized, all are extinct except for six species in two surviving genera, Nautilus and Allonautilus. Other living cephalopods, all predators in the subclass Coleoidea with internal shells, number over 725 species, with many more likely to be recognized. See also: Coleoidea; Mollusca
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. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews 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 17,000 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