What it was
A soft dome with a frilled skirt round the edge, usually a few centimeters long. More than a thousand have been found, from around 555 million years ago.
How we know
On the same slabs, again and again, are fans of paired scratches. Kimberella anchored itself, reached out with a snout tipped by two teeth and raked the bacterial mat toward its mouth. It never grazed its own old fans. It could tell where it had already been.