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
Find out more about Cnidaria from the