The plated animals — now identified as belonging to the Characodictyon genus — lived sometime between 717 million and 812 million years ago, a time period in which single-cell organisms thrived just before the first “Snowball Earth” event, when the planet plunged into a deep freeze and became covered in vast ice sheets. Cohen suspects the deep freeze killed off these spiny microorganisms. (On the flip side, at least one recent study suggests the deep freeze spurred the emergence of complex life.)
Using scanning electron microscopy, Cohen and Macdonald, along with collaborators at UCLA, created 3-D images of the fossils. The images revealed the animal was covered in plates, each about 20 microns wide (one-fifth the width of a human hair) and arranged in a honeycomb pattern, with teethlike spines jutting out and rimming the perimeter.
Story: Jeanna Bryner, LiveScience | Photo: Cohen, Macdonald