Fossils of the Ediacara Biota
from SA
Spriggina fouldersi
Spriggina floundersi, the state fossil of South Australia, is only found within the Rawnsley Quartzite of South Australia. Described as being bilaterally symmetrical and having a broadly ‘segmented’ body plan, with a ‘head’ and ‘tail’ end. Not much is known about this enigmatic organism, and its preserved features may not be homologous to those seen in modern animals. While hypothesised to have been capable of movement, no direct evidence has been published. About 2–5 cm long.
Text: Tory L. Botha and Diego C. García-Bellido, UofA and SAM
Dickinsonia costata
Originally described by Reg Sprigg in 1947, Dickinsonia costata was first discovered in the late Ediacaran of South Australia. It lived in shallow, sandy marine environments on what was formerly the sea floor.
Dickinsonia costata, one of the most common taxa in the biota, is an apparently bilaterally-symmetrical organism found in the Ediacara Member of the Rawnsley Quartzite, Flinders Ranges, South Australia and the White Sea in Russia (~555 Ma). Leaving ‘footprints’ behind, Dickinsonia is thought to have fed by external digestion of the underlying microbial mat, creating a perfect impression, left behind when moving onto fresh mat ahead. This oval shaped organism reached 10 cm in length.
Specimen number: SAMA P40135 (South Australian Museum gallery specimen)
Text: Tory L. Botha and Diego C. García-Bellido, UofA and SAM
Tribrachidium heraldicum
Named for its similarity to the triskelion heraldic symbol, this small (3 – 40 mm) animal was first described from the Ediacara Member of the Rawnsley Quartzite in the Flinders Ranges of South Australia. This is where the specimen scanned here originates from. It has since been found in Ukraine, Russia and India.
Tribrachidium heraldicum, a triradial spiral organism found in abundance in the Rawnsley Quartzite of South Australia and the White Sea, Russia. It’s thought to have utilised passive suspension feeding as its morphology has been shown to slow and redirect water flow in a way that particles would precipitate from the water column at the apex of the organism. Grew to about 5 cm in diameter.
Specimen number: SAMA P12898 (Holotype)
Text: Tory L. Botha and Diego C. García-Bellido, UofA and SAM