The dawn of movement
On the wave-battered coast of Newfoundland's Avalon Peninsula, surfaces of rock preserve a deep moment in Earth's history: the first faint scratchings of animal life on the move. These are not fossilized bones or shells, but trace fossils—impressions left on ancient deep-sea mud 565 million years ago. The site, part of the Mistaken Point Ecological Reserve, a UNESCO World Heritage Site, shows the seafloor from the Ediacaran Period. At that time, this part of Newfoundland was a deep marine environment, located between 40° and 65° South latitude.
The organisms that roamed this primordial seabed were soft-bodied, leaving no physical remains. Their only legacy is the trails they etched into the mud. Among the more than 70 fossilized trails identified, the most significant are named Helminthoidichnites tenuis. These simple, horizontal traces, typically 1 to 3 millimeters wide, represent the oldest definitive evidence of locomotion by macroscopic animals. The creatures that made them were likely small, worm-like animals. Analysis suggests they moved by using a muscular, foot-like organ, similar to how a modern sea anemone shuffles across the sand. This indicates the presence of muscular tissue, an important evolutionary development.