The majority of animals more complex than jellyfish and other Cnidarians are split into two groups, the protostomes and deuterostomes, the latter of which contains chordates.[20] It seems very likely the 555 million-year-old Kimberella was a member of the protostomes.[21][22] If so, this means the protostome and deuterostome lineages must have split some time before Kimberella appeared—at least 558 million years ago, and hence well before the start of the Cambrian 541 million years ago.[20] The Ediacaran fossil Ernietta, from about 549 to 543 million years ago, may represent a deuterostome animal.[23]