More than half a billion years ago, a worm-like creature wriggled its last, creating a groove preserved as a fossil that offers new insights into some of the earliest animal movement.
The origins of movement in animal species remains fairly murky, though there is evidence of "directional movement" -- as opposed to the meandering drift of a jellyfish for example -- as early as 560 million years ago.
The fossils provide the first "direct supporting evidence" of early movement by a segmented animal, Shuhai Xiao, a professor at
Virginia Tech university's geosciences department, told AFP.