Scientists announced Wednesday that they have discovered the oldest known footprints of an animal.
The footprints, belonging to an unknown invertebrate, date back to around 541 million years ago. The footprints were discovered in southern China and analyzed by scientists in the United States and China.
The tracks are only a few millimeters in diameter and dot the soft gray limestone found in the Yangtze Gorges region of China.
The tracks are actually older than any fossil of a creature with legs, so scientists are puzzled by what created the footprints. They believe it was some sort of worm or insect-like creature.
The research was published Wednesday in the journal Science Advances by scientists from the Chinese Academy of Sciences and Virginia Tech.
“This is considered the earliest animal fossil footprint record,” the researchers wrote in the report.
The scientists said that it appeared the ancient creature paused several times while it was crawling along the ancient mud, perhaps to feed off a mat of microbes or burrow to find oxygen.
Because the tracks are older than any known fossil of a legged animal, they are crucial for understanding how early animals evolved during the infant days of life on earth.
“These trace fossils include burrows and possible trackways that are preserved in close proximity and are apparently connected,” the scientists noted in an introduction to the report.
“They were probably made by millimeter-sized animals with bilateral appendages and can provide important insights into early bilaterian evolution and behaviors.”
