Nemiana simplex, a White Sea Ediacaran fossil (upper Vendian) in the sandstone shales from the Novodnestrovsky Quarry, Podolia, Ukraine. The ediacaran biota existed from about 580 to 540 million years ago, but the whole ecosytem biota largely dissappeared during the Cambrian explosion when most modern groups originated. Paliy (1976) identified Nemiana as a coelentrate, but not all the expected structures are clear. Some think it is a burrowing anenome with these structures as the base. Others suggest it may be a giant Chlorophyte algae similar to the living Ventricaria. Individual spheres of these alage are single cells with surprising rigidity.