A diverse, well preserved fossil assemblage consisting of micro- and macro-sized molluscs, sponge spicules, chancelloriid sclerites, hyolithelminth tubes, tommotiids, protoconodonts and lobopodian sclerites from the Third Plain Creek Member (Pararaia bunyerooensis Zone) of the Mernmerna Formation in the eastern Flinders Ranges, Arrowie Basin, South Australia is described. Molluscs are represented by hyoliths, helcionellids and a single bivalve species. The enigmatic helcionellid taxon Marocella mira is formally described for the first time from the Arrowie Basin and forms the basis of a new helcionellid family, the Marocellidae. Sclerites of the lobopodian Microdictyon jinshaense Zhang and Aldridge are described for the first time outside South China. Whilst many of the taxa are biostratigraphically long ranging, several species in the assemblage facilitate correlation across the Arrowie Basin, with the neighbouring Stansbury Basin to the south, and also with faunas from other Cambrian palaeocontinents, including Antarctica, South China and Laurentia.