Palaeos: Palaeos Invertebrates
Metazoa Radiata

Radiata

Animals with Radial Symmetry

 


Polyorchis pencillatus - Red Eye Medusa
Phylum Cnidaria - Class Hydrozoa - Order Anthomedusae - Family Polyorchidae

image copyright © Keith Clements and Jon Gross Marine Life of the Northeast Pacific


Included here are invertebrates with radial symmetry: all longitudinal planes are equal around central body axis. They are also diploblastic (possessing only two germ layers, an ectoderm and endoderm, but, unlike the Bilateria, no mesoderm. Only two phyla belong here - the Cnidaria and Ctenophora


Radiata after Conway Morris, 1993

<==o RADIATA 
   |?- CTENOPHORA
   `--o CNIDARIA 
      |--+-- TRILOBOZOA
      |  `-- ANABARITIDA
      `--+--o HYDROZOA 
         |  |-- HYDROZOA
         |  `--o CHONDROPHORA
         |     |-- Porpitidae
         |     `-- Velellidae
         `--+--+-- FASCICULIDA
            |  `--+-- TENTACULATA
            |     `-- NUDA
            `--+--+--+-- SCYPHOZOA (medusa, jellyfish)
               |  |  `--o CUBOZOA
               |  |     `--o CUBOMEDUSAE
               |  |        |-- Carybdeidae
               |  |        `-- Chirodropidae
               |  `--+-- CONULARIDA
               |     `-- CARINACHITIIDA
               `--o ?ANTHOZOA
                  |-- XIANGUANGIIDA
                  |?- ALCYONARIA
                  `--+-- PENNATULACEA
                     `--+-- ECHMATOCRINIIDA
                        `-- ANTHOZOA

References

Conway Morris, S., 1993

Fautin, DG & SL Romano (2000)

Hou & Bergström, 1997


 


images not loading? | error messages? | broken links? | suggestions? | criticism?

contact us

page uploaded 7 April 2002, last modified 2 May 2003
checked ATW050806
text content © Mikko Haaramo
this material may be freely used as long as attribution is given