More recently, another missing link in the evolutionary puzzle sent revelations through the scientific community. From studying multiple miniscule fossilised burrows found in Nilpena in 2005, Droser and evolutionary biologists had long predicted that in the same period – around 555 million years ago – a more complex creature compared to other Ediacaran Biota was on the move, contracting muscles across its body to travel. In 2020, using 3D laser scanner technology, Droser and her team were able to recreate the creature – a plump, wormy blob, the size of a grain of rice. It had a notable difference compared to other lifeforms in existence at that time: it was the first animal ever to have a front and a back, a mouth, gut and rear end – called a “bilaterian”.
This meant Ikaria wariootia, as they named the blob, could possibly be the animal that ate and excreted its way on a long, transformative journey that, eventually, resulted in humans. “It’s certainly the oldest bilaterian that we know of,” Droser said.
“There are places that have parts of the story, and there are places with phenomenal fossils, but the Flinders has this complete packaging that is really accessible. We can go back in time and see how life unfolded. The record is unparalleled,” Droser said.
Before pushing on from Brachina Gorge, we pedalled a few minutes off the mapped Mawson Trail route to see another remarkable point of interest. A bronze disc called the Golden Spike is nonchalantly nestled in the gorge’s lower rib lines at Enorama Creek. Resembling a large Olympic medal, it marks the geological starting point of the Ediacaran Age – a time when the early moments of an evolutionary process gave rise to animals, the dawn of life and the journey of humanity… all waiting to be stumbled upon by seven slightly lost and oblivious mountain bikers.
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