Paleontologists May Have Uncovered One of Earth’s Oldest Moving Animals in Australia’s Outback

Paleontologists have recently unearthed a significant discovery in the Nilpena Ediacara National Park, located in the remote outback of South Australia.

The find, a species named Quaestio simpsonorum, is believed to be one of the oldest moving animals. This remarkable fossil, dating back approximately 555 million years, offers a unique window into the evolution of life during the Ediacaran Period, a critical era when complex multicellular organisms first appeared on Earth.

Quaestio Simpsonorum: A Pioneer in Mobility and Evolutionary Complexity

The fossilized remains of Quaestio simpsonorum were discovered by a team led by Scott Evans, an assistant professor of geology at Florida State University. Evans, along with paleontologists from institutions such as the University of California, Riverside, and the South Australian Museum, have been exploring the fossil beds of Nilpena for years. The area has long been recognized as one of the world’s richest sources of ancient fossils from the Ediacaran Period, but the discovery of Quaestio has added new layers of understanding to the study of early life forms.

Described as a small creature, roughly the size of a human palm, Quaestio stands out due to its unusual question-mark shape, which clearly distinguishes the left and right sides of its body. This left-right asymmetry is a hallmark of evolutionary complexity, and its presence in this ancient species is considered a breakthrough. “There aren't other fossils from this time that have shown this type of organization so definitively,” said Evans. He further emphasized the importance of this asymmetry as an evolutionary milestone, adding that “having left–right asymmetry shows some level of complexity, and it is exciting to be able to recognize it at all in these earliest fossil animals.”

The discovery is particularly significant because it offers a rare glimpse into the early development of animal life. As Evans explained, "animals today use the same basic genetic programming to form distinct left and right sides, so we can be reasonably confident those same genes were operating to produce these features in Quaestio." This suggests that the genetic mechanisms which govern bilateral symmetry in modern animals were already in place more than half a billion years ago, offering insights into how these early genetic patterns shaped the course of evolution.

Behavior and Environment: A Prehistoric 'Roomba' of the Seafloor

Quaestio simpsonorum is also notable for its ability to move independently, a rare trait for life forms of its era. The creature is believed to have behaved much like a primitive Roomba, slowly moving along the seafloor in search of nutrients. It likely fed on the microbial mats that covered the ocean floor, which were composed of microscopic algae, bacteria, and other microorganisms. These mats provided a rich source of organic material, which Quaestio vacuumed up as it moved, a behavior that researchers believe was essential for its survival in the nutrient-rich, yet competitive, environment of the Ediacaran seas.

The fossil beds at Nilpena Ediacara National Park not only contain the body fossils of Quaestio, but also trace fossils—impressions left behind in the ancient seafloor that clearly show the creature’s movements. Ian Hughes, a graduate student at Harvard University and one of the paleontologists involved in the excavation, described the moment of discovery: “One of the most exciting moments when excavating the bed where we found many Quaestio was when we flipped over a rock, brushed it off, and spotted what was obviously a trace fossil behind a Quaestio specimen—a clear sign that the organism was motile; it could move.” This combination of body and trace fossils is exceedingly rare and provides direct evidence of how this ancient animal moved and interacted with its environment.

The trails left by Quaestio simpsonorum on the seafloor offer a detailed glimpse into its behavior. As it moved along the ocean floor, it likely consumed the nutrients present in the slimy, organic mats, much like a modern vacuum cleaner. This behavior suggests that even at this early stage of evolution, animals were developing strategies to survive and thrive in their environments by seeking out the resources they needed to grow and reproduce.

Quaestio Simpsonorum's Evolutionary Significance

The discovery of Quaestio simpsonorum is not just about understanding a single species, but about unlocking the broader mysteries of early animal evolution. The presence of left-right asymmetry and the animal’s ability to move autonomously point to a significant step in the development of complex life on Earth. As Mary Droser, a distinguished professor of geology at UC Riverside and one of the lead scientists on the project, explained: “It’s incredibly insightful in terms of telling us about the unfolding of animal life on Earth. 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.”

Understanding how early animals like Quaestio evolved can help scientists explore the processes that led to the rise of complex life forms, including humans. Droser emphasized the importance of studying these early fossils, as they provide clues about the environmental pressures and genetic mechanisms that influenced the development of animal life. “Determining the gene expressions needed to build these forms provides a new method for evaluating the mechanisms responsible for the beginnings of complex life on this planet,” she said.

Continuing Research and Future Discoveries

While the discovery of Quaestio simpsonorum has been a major milestone, the work at Nilpena Ediacara National Park is far from complete. Researchers have been excavating in the area for decades, unearthing a wealth of fossils that provide insights into the earliest animal ecosystems. The park itself spans nearly 150,000 acres, and paleontologists are constantly finding new fossils that shed light on the diversity of life during the Ediacaran Period.

As Ian Hughes remarked, “We’re still finding new things every time we dig. Even though these were some of the first animal ecosystems in the world, they were already very diverse. We see an explosion of life really early on in the history of animal evolution.” The fossil beds continue to yield new discoveries that enrich our understanding of how early life on Earth evolved and adapted to changing environmental conditions.

The team, which includes both scientists and volunteers, plans to continue excavations at Nilpena, hoping to uncover more about the complex ecosystems that existed over half a billion years ago. Each new discovery adds another piece to the puzzle of early animal life, helping researchers better understand the evolutionary processes that shaped the world we know today.