Cnidarians

Reconstruction of Essexella asherae modified from Foster (1979)

Cnidarians is the group that includes the jellyfishes, corals, sea anemones and hydroids. Corals have a very long fossil record, because they have a hard skeleton, but the other kinds of cnidarians are relatively rare in the fossil record. The soft tissue preservation of the Mazon Creek nodules gives us fine examples of fossil jellyfish, like this Essexella

Find out more about Cnidaria from the Berkeley site.