Editing Bryozoa (section)

====Grouping into the Lophophorata====

By 1891 bryozoans (ectoprocts) were grouped with [[phoronid]]s in a super-phylum called "Tentaculata". In the 1970s comparisons between phoronid larvae and the [[cyphonautes]] larva of some gymnolaete bryozoans produced suggestions that the bryozoans, most of which are colonial, evolved from a semi-colonial species of phoronid.<ref name="Nielsen2001AnimalEvoPhylumEctoprocta">{{cite book |last=Nielsen |first=C. |title=Animal evolution: interrelationships of the living phyla |publisher=Oxford University Press |year=2001 |edition=2 |pages=244–264 |chapter=Phylum Ectoprocta |isbn=978-0-19-850681-2 |chapter-url=https://books.google.com/books?id=UmCg6c0HkqMC&q=ectoprocta%20bryozoa%20phylogeny&pg=PA257 |access-date=2009-08-14 |archive-date=8 March 2023 |archive-url=https://web.archive.org/web/20230308183241/https://books.google.com/books?id=UmCg6c0HkqMC&q=ectoprocta%20bryozoa%20phylogeny&pg=PA257 |url-status=live }}</ref> [[Brachiopod]]s were also assigned to the "Tentaculata", which were renamed [[Lophophorata]] as they all use a [[lophophore]] for filter feeding.<ref name="Halanych2004AnimalPhylogeny" />

The majority of scientists accept this,<ref name="Halanych2004AnimalPhylogeny" /> but Claus Nielsen thinks these similarities are superficial.<ref name="Nielsen2002PhyloPosOfEntoproctaEctoproctaPhoronidaBrachiopoda">{{cite journal |last=Nielsen |first=C. |date=July 2002 |title=The Phylogenetic Position of Entoprocta, Ectoprocta, Phoronida, and Brachiopoda |journal=Integrative and Comparative Biology |volume=42 |issue=3 |pages=685–691 |doi=10.1093/icb/42.3.685 |pmid=21708765 |doi-access=free }}</ref> The Lophophorata are usually defined as animals with a lophophore, a three-part coelom and a U-shaped gut.<ref name="Nielsen2001AnimalEvoPhylumEctoprocta" /> In Nielsen's opinion, phoronids' and brachiopods' lophophores are more like those of [[pterobranch]]s,<ref name="Nielsen2002PhyloPosOfEntoproctaEctoproctaPhoronidaBrachiopoda" /> which are members of the phylum [[Hemichordata]].<ref>{{cite web |url=http://www.ucmp.berkeley.edu/chordata/hemichordata.html |access-date=2008-09-22 |title=Introduction to the Hemichordata |publisher=University of California Museum of Paleontology |archive-url=https://web.archive.org/web/20190201080336/http://www.ucmp.berkeley.edu/chordata/hemichordata.html |archive-date=1 February 2019 |url-status=dead }}</ref> Bryozoan's tentacles bear cells with multiple [[cilia]], while the corresponding cells of phoronids', brachiopods' and pterobranchs' lophophores have one cilium per cell; and bryozoan tentacles have no hemal canal ("blood vessel"), which those of the other three phyla have.<ref name="Nielsen2002PhyloPosOfEntoproctaEctoproctaPhoronidaBrachiopoda" />

If the grouping of bryozoans with phoronids and brachiopods into Lophophorata is correct, the next issue is whether the Lophophorata are [[protostome]]s, along with most invertebrate phyla, or [[deuterostome]]s, along with [[chordate]]s, [[hemichordate]]s and [[echinoderm]]s.

The traditional view was that lophophorates were a mix of protostome and deuterostome features. Research from the 1970s onwards suggested they were deuterostomes, because of some features that were thought characteristic of deuterostomes: a three-part coelom; radial rather than spiral cleavage in the development of the embryo;<ref name="Halanych2004AnimalPhylogeny" /> and formation of the coelom by [[enterocoely]].<ref name="Nielsen2002PhyloPosOfEntoproctaEctoproctaPhoronidaBrachiopoda" /> However the coelom of ectoproct larvae shows no sign of division into three sections,<ref name="Nielsen2001AnimalEvoPhylumEctoprocta" /> and that of adult ectoprocts is different from that of other [[coelomate]] phyla as it is built anew from epidermis and mesoderm after metamorphosis has destroyed the larval coelom.<ref name="DewelWinstonMcKinney2001Deconstructing" />