What is Radiata?
{{Taxobox | name = Radiata | fossil_range = [[Ediacaran]] – Recent | image = Moon jelly - adult (rev2).jpg | image_caption = A moon jellyfish, ''Aurelia aurita'' | regnum = [[Animal]]ia | subregnum = [[Eumetazoa]] | unranked_phylum = '''Radiata''' | unranked_phylum_authority = [[Carolus Linnaeus|Linnaeus]], 1758 | subdivision_ranks = [[Phylum|Phyla]] | subdivision = * [[Cnidaria]] * [[Ctenophora]] * † [[Trilobozoa]] }} The '''Radiata''' is a super[[phylum]] which includes both the [[echinoderm]]s and the [[ctenophore]]s. It is not part of the usual [[classification]] system, and is not used by all biologists.<ref>Nielsen, Claus 2002. ''Animal evolution: interrelationships of the living phyla''. 2nd ed, Oxford University Press. Eumetazoa p51; Cnidaria p60; Ctenophora p72.</ref><ref>Valentine, James 2004. ''On the origin of phyla''. Chicago University Press. p214 Cnidarians and Cnidariomorphs; p228 Ctenophora</ref> The group includes the [[Symmetry (biology)#Radial symmetry|radially symmetric]] animals of the [[Eumetazoa]]. The echinoderms, however, are members of the [[Bilateria]], because they exhibit [[bilateral symmetry]] in their developing stages. Their radial symmetry is secondary. Thomas Cavalier-Smith in 1983 defined a subkingdom called Radiata consisting of the [[Phylum|phyla]] [[Sponge|Porifera]], [[Myxozoa]], [[Placozoa]], [[Cnidaria]] and [[Ctenophora]] in Radiata, that is, all the animals that are not in [[Bilateria]]. The ''[[Kingdom (biology)#Five kingdoms|Five Kingdom]]'' classification of Lynn Margulis and K.V. Schwartz keeps only Cnidaria and Ctenophora in Radiata. [[Clade|Cladistic]] classifications do not recognize Radiata as a clade. The radiata, in this sense, are [[diploblastic]], meaning they have two primary germ layers: endoderm and ectoderm. Cavalier-Smith's use of the term Radiata includes animals with a single germ layer such as sponges. Although radial symmetry is usually given as a defining characteristic of radiates, a few members of the class [[Anthozoa]], which are now co