This is a really cool fossil. Think of how rare it must be for
an animal without a hard shell or skeleton to be preserved
as a fossil. Unfortunately, this is the only specimen
of Anthracomedusa that we have in our collections at
UCMP. Other specimens from Mazon Creek better reveal the
square shape of the bell,
as well as the four bunches of tentacles.
Click on the buttons below to find out more about Cubozoa.
Sources:Foster, Merrill W. 1979. Soft-bodied coelenterates in the Pennsylvanian of Illinois. pp. 191-267 In: Mazon Creek fossils. edited by Nitecki, Matthew H. Academic Press, New York, NY.