Late Proterozoic fossils, first described from Ediacara, Australia, dated to the Ediacaran period. They come from a shallow, littoral, marine environment and the animals appear to have been stranded on mudflats or in tidal pools. About 30 genera are known and include: medusoids (jellyfish), e.g. Medusina mawsoni and Medusinites; pennatulaceans (soft corals), e.g. Charniodiscus; annelid worms, e.g. Spriggina; and Dickinsonia, up to 1 m long, which may have resembled an anthozoan polyp, but has been variously assigned to the annelids, medusoids, and to a phylum of its own. There are also ovoid or discoid forms of unknown affinity. Since the fossils were first described by M. F. Glaessner in 1961 similar faunal types of equivalent age have been found elsewhere in the world.