Lochhead, John H. London, United Kingdom.
McLaughlin, Patsy A. Shannon Point Marine Center, Western Washington University, Anacortes, Washington.
Last reviewed:October 2019
- Related Primary Literature
- Additional Reading
A group of tiny marine crustaceans (body length 2.0–4.0 mm or 0.08–0.16 in.), discovered in 1954. Initially, cephalocarids were thought to be a living representation of what the primordial crustacean looked like. In recent years, that view has changed, with the Branchiopoda currently postulated to represent the most primitive of extant major crustacean taxa. In the classification of J. W. Martin and G. E. Davis (2001), the Branchiopoda are basal, whereas the Cephalocarida are positioned between the Remipedia and Maxillopoda, suggesting a more advanced evolutionary position for the class. Nonetheless, in their discussion of “most primitive,” Martin and Davis acknowledge that the question is still unresolved. At present, the Cephalocarida comprise ten species, assigned to five genera in one family. They have been found in flocculent surface deposits of mud or silty sand, from the intertidal zone down to depths of 5000 ft (1500 m), on the shores of all continents except Europe. Population densities up to an average of 16 individuals/ft2 (177/m2) have been recorded. See also: Brachiopoda; Crustacea
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 10,000 highly qualified scientists and 45 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