Armillifera
Armillifera parva is an Ediacaran marine animal, that existed on Earth about 555 million years ago. It was first described by Mikhail Fedonkin in 1980. Its fossils were discovered in the White Sea area, Arkhangelsk Region, Russia. These fossils of "A. Parva" were restricted to almost the same stratigraphic range as the fossils of another creature , named "Kimberella", but were rarely found. Morphology. "Armillifera" is bilaterally symmetric, oval shaped animal from the Ediacaran period. It's convex ,which is in the center, possess a flattened Classification. The 'shell' of "Armillifera" possess a lack of a grow line, and the  bilateral symmetry that "Armillifera" has suggested that it was likely to be an actively moving organisms in its environment. The fact that the deep hook-shaped depressions in its central region are arranged accordingly to glide reflection symmetry, may refer its connection to Proarticulate. But the resemblance of the shell-like structure may not be the ultimate evidence to support that, so it's still unclear which phylum "Armillifera" belonged to.