The oldest fossil faunas of South Australia

A critical review of earlier references to Precambrian fossils in South Australia shows that Radiolaria could be present but that other animal remains listed or described by earlier authors have been wrongly interpreted. There is no evidence for the presence of Arthropods in this material.The fauna described bySprigg from the early Cambrian sandstone and quartzite of Ediacara consists not only of Medusae. Recent studies have shown that it includes specimens resembling the types ofPteridinium andRangea from the Nama Series of Southwest Africa. They are now considered as related to living Pennatulacea. In addition, there are present the annelidSpriggina, possibly Siphonophora, and at least two entirely new forms of invertebrates.This assemblage is followed by a sequence of undoubted Lower Cambrian faunas from the lowest Archaeocyatha horizon up to theProtolenus-Zone. The Ediacara fauna which consists only of soft-bodied animals is entirely unlike any known Cambrian fauna. This fact supports the view that it is Precambrian.