Dickinsonia fossil

What on Earth? May 30th

Today’s answer is Dickinsonia fossil. The portion shown in the question on Facebook and Instagram is outlined in the image above.

The fossils are animals which lived during the Ediacaran period more than 500 million years ago. Until recently it was not known whether Dickinsonia were animals or algae. Researchers have shown that Dickinsonia is indeed an animal.

South Australia is one of the world’s richest Ediacaran fossil localities. Fossils are found in a rock unit called the Ediacara Member throughout the Flinders Ranges where this image was taken.

Our image is a bit unusual in that it shows two species – Dickinsonia costata and Dickinsonia tenuis. The fossil of D. costata is 132.8 mm long, while D. tenuis is 77.9 mm long.

Reference:

Gregory J. Retallack (2007) Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil, Alcheringa, 31:3, 215-240, LINK

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