Ediacara

550 million years in the making!

The Flinders Ranges are one of Australia’s great landscapes, a window into deepest, almost unfathomable time and within the rocks is evidence of the earliest animal life on Earth – the dawn of animal life. This is where the Ediacara fossils were first discovered in 1946 by Reg Sprigg, who named them after the Ediacaran Hills, and where the international reference point for the Ediacara geological time period is centred.

 

“The Ediacara fossils of South Australia are absolutely the key to our understanding of how animal life unfolded on Planet Earth”

Dr Mary Droser

Nilpena Station in South Australia’s Flinders Ranges may have been a pastoral property for 150 years, but long before livestock roamed, it was home to an array of ancient creatures that scientists say mark the dawn of animal life. 

Each year, for the past 18-19 years, leading US geologist Dr Mary Droser, from the University of California Riverside, swaps the big city for the South Australian bush to study what has been left behind – Ediacara fossils which she says date back at least 550 million years. “There is this group of fossils that occurs before things have skeletons, and there are these soft-bodied organisms that lived for 40 million years. This is their fossil record, so it’s Earth’s oldest animal ecosystem and the Flinders Ranges has the best record.”

There are several notable ediacara fossil fields in the world, but Dr Mary Droser says the one she works on at Nilpena (in close collaboration with Dr Jim Gehling AO from the South Australian Museum) is a stand-out. “You go to Namibia and you get certain types of fossils that are thought to be younger than this and then Newfoundland where you get ones that are dated older than this,” she said. “But at Nilpena we have all of these fossils …..we actually have everything and there’s no other site that has all of these things. It is really is absolutely extraordinary. The Ediacara fossils of Nilpena are a unique part of our planet’s story – researchers have been able to excavate fossil beds that preserve snapshots of an ancient seafloor as animal life unfolded millions of years ago.  There is no other place in the world where this has been done for fossils of any age.”

The Nilpena site is the subject of considerable research, including that supported by NASA, but its significance, and remoteness, makes it vulnerable to looting. It is the protection of this site which created the impetus for establishment of the Flinders Ranges Ediacara Foundation.

“We want the fossils to continue to be the subject of research that keeps South Australia at the forefront of science in this field, because they provide unparalleled insight into how animal life evolved in a changing environment on Earth”.

Mary Lou Simpson, Foundation Chair

Wonders of the Ediacaran

Palaeontologist Dr Jim Gehling AO is one of the world’s leading researchers of the oldest complex animals on Earth and has studied Ediacaran fossils and rocks in the Flinders Ranges for over 40 years, as well as fossil sites on Kangaroo Island, as well as Canada, the USA, the UK, China and Namibia. He has worked closely with Dr Droser and briefly describes some of these enigmatic creatures.

  

 

Mawsonites spriggi was likely an anemone-like soft coral preserved where it lived on the sea floor

Rugoconites Enigmaticus was a disc-like sponge with branching ribs that helped it collect food from passing water.

Dickinsonia Tenuis is related to the species that put Reg Sprigg on the map. It was a flexible, segmented mat-shaped animal. The related Dickinsonia rex can be the size of a bathmat 

Spriggina foundersi. This is the earliest known organism with a head end and a differentiated body, suggesting that it was near the base of the branch of animals that we call ‘arthropods’ (jointed legged animals like centipedes, shrimp and slaters) 

Charniodiscus arboreus may have been a soft coral with polyps arranged along its branches. Such frond fossils are very rare, probably because they were torn off by the storms that smothered these Ediacara seafloor communities with sand 

Parvanorina minchami has a median ridge and head arc, that may mean it is another kind of early arthropod. As yet there is no evidence that its internal appendages were jointed

In 2004 the International Commission on Stratigraphy gave the name ‘Ediacaran’ to the period between 542 and 635 million years ago that was dominated by these weird and wonderful creatures, some of which bear Sprigg’s name.  “Animals of the Ediacaran period were generally soft-bodied marine creatures and all that remains of them are faint impressions left in sandstone,” says Dr Gehling. “The sand is set and cast in the shape of the body or at least part of the body.” It has puzzled scientists how organisms so soft could have left such a lasting impression in sandstone but Gehling believes that bacteria, attracted by the slime covering the creatures, absorbed minerals from the carcasses, and used pyrite to weld sand grains together to form a tough ‘death mask’ to preserve the shape of the animal. Preservation was aided by the fact that at the time there appeared to be no animals with teeth to much up the remains, or burrowing animals.  

The South Australia State Fossil Emblem is the unique Spriggina – and fittingly, the emblem of the Foundation – one of the most significant of Ediacaran fossils, which is only known from the Flinders Ranges here in South Australia. 

  

Spriggina floundersi

The South Australian government is pursuing World Heritage Listing for this record of early life in the Flinders Ranges and the Foundation is proud to be supporting this bid.