Conulariids
Conulariids are puzzling, layered pyramid shapes found in the fossil record. Thought to be part of the Cnidaria, a phylum of animals that includes corals and jellyfish, there are no known equivalents of these animals alive today. As fossilised conulariids represent only the hard parts of these animal’s bodies, scientists have to make an educated guess as to what the living animal may have looked like.
Sketch of fossil conulariid from the Tasmanian Permian (Paraconulariia derwentensis, Parfrey 1982)