Jump to ContentJump to Main Navigation
Animal EvolutionInterrelationships of the Living Phyla$
Users without a subscription are not able to see the full content.

Claus Nielsen

Print publication date: 2011

Print ISBN-13: 9780199606023

Published to Oxford Scholarship Online: December 2013

DOI: 10.1093/acprof:oso/9780199606023.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 20 October 2021

Phylum Bryozo (Ectoprocta)

Phylum Bryozo (Ectoprocta)

(p.208) 38 Phylum Bryozo (Ectoprocta)
Animal Evolution

Claus Nielsen

Oxford University Press

The phylum Bryozoa (Ectoprocta) is comprised of approximately 6,000 living species of sessile, colonial, aquatic organisms and has an extensive fossil record that dates back to the Early Ordovician. There are two known classes of bryozoans, Gymnolaemata and Phylactolaemata. Extant gymnolaemates are generally classified in Eurystomata, characterised by a ‘normal’ embryology with planktotrophic or lecithotrophic larvae, and Cyclostomata (the only living order of the group Stenolaemata), which possess specialised gonozooids and exhibit polyembryony. All zooids develop by budding, making it impossible to relate their orientation to the larval organisation. All gymnolaemates display similar settling behaviour and the first phases of the metamorphosis, but the later stages vary considerably. Cyclostomes have a highly specialised type of reproduction with polyembryony. The Bryozoa has an unquestioned monophyly, although this is not supported by some earlier molecular phylogenies.

Keywords:   bryozoans, Bryozoa, Gymnolaemata, Phylactolaemata, gymnolaemates, Eurystomata, embryology, Cyclostomata, polyembryony, cyclostomes

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .