Question mark on back marks the oldest asymmetrical animal found

Scientists discovered an ancient marine creature named Quaestio simpsonorum in South Australia's Nilpena Ediacara National Park. Described in a study published in the journal Evolution & Development, this 555 million-year-old organism represents one of the earliest examples of complex life on Earth.

Quaestio simpsonorum is characterized by its distinctive pancake-like shape and a unique question mark-shaped ridge on its back. This left-right asymmetry marks it as the first known organism to exhibit such a trait, indicating a significant level of genetic complexity and complex body organization. According to Live Science, asymmetry allowed complex organisms like humans to evolve body parts with specific placements, such as a heart on the left side and a liver on the right.

"There are no other fossils from this era that have demonstrated this type of organization so definitively," said Professor Scott Evans from Florida State University, the lead author of the study. "This is especially interesting because it is also one of the first animals that was able to move by itself."

Mary Droser, the lead scientist at Nilpena and a distinguished professor of geology at the University of California, Riverside, has been excavating at the site for decades. She was also Evans' former doctoral adviser.

"It's incredibly insightful in terms of telling us about the unfolding of animal life on Earth," she said.

Quaestio simpsonorum is not only noteworthy for its asymmetry but also for its ability to move independently, a trait confirmed only for a few species of the era. Fossilized tracks were found directly behind one of the specimens, indicating that the creature moved along the ocean floor.

The asymmetry of Quaestio simpsonorum would have been a groundbreaking evolutionary trait during the Ediacaran period, long before the Cambrian explosion. This period, around 635 million to 541 million years ago, saw the emergence of early complex life forms.

The creature's unique features suggest a certain level of genetic complexity. "Since modern animals use the same basic genetic program to form individual left and right sides, we can be sure that the same genes were acting to form these features in Quaestio, an animal that became extinct more than half a billion years ago," Evans said.

The park opened to the public in early 2023 and is part of a bid to be recognized as a UNESCO World Heritage Site due to its valuable records of Earth's living history. (Science Alert)

Ian Hughes, a member of the research team, emphasized the site's significance. "We're still finding new things every time we dig," he said.

The excavation at Nilpena has been supported by organizations including NASA, the Australian Research Council, and the Agouron Institute, with additional funding from the Flinders Ranges Ediacara Foundation. The species name simpsonorum honors Mary Lou and Antony Simpson, who established the foundation to support work in the area, according to IFLScience.

"Studying the history of life through fossils tells us how animals evolve and what processes cause their extinction, be it climate change or low oxygen," Droser said. "We're the only planet that we know of with life, so as we look to find life on other planets, we can go back in time on Earth to see how life evolved on this planet."

Astrobiology, Ancient Origins, Popular Mechanics, The Mirror, Newsweek, Science Alert, and Vice News reported on the finding, among other websites.

The article was written with the assistance of a news analysis system.