Eldonioid

Eldonioids or velumbrellids are an extinct clade of disc-shaped cambroernids which lived in the early to middle Paleozoic (Cambrian to Devonian). Depending on the researcher, the clade is either considered to either be the class Eldonioidea (containing only the order Velumbrellida) or be the order Eldonida. The lifestyle of eldonioids is still an unresolved question; some authors reconstruct eldonioids as free-floating planktonic predators similar to jellyfish, while others argue that they were passive detritivores, embedded within the seabed for much of their life.