Article: Mode of life of the Middle Cambrian eldonioid lophophorate Rotadiscus
The discs of the alleged ' medusoids' Rotadiscus from the recently discovered Mid Cambrian soft-bodied Kaili fauna in South China are commonly overgrown by shelled epizoans of unknown affinities. Most are attached to the convex side of the disc, near its margin. Towards the disc centre only small shells occur usually, which suggests that their growth was inhibited by an anoxic environment under the disc. The eldonioids were thus sedentary animals, analogous to Recent deep-water thecocyathid corals, with the discs passively lying on the mud surface with the convex side of the disc orientated downward.