About 600 million years ago, mysterious, frondlike creatures unlike anything found on Earth today filled the primeval seas. Now, new research is shedding light on how these sea creatures, called rangeomorphs, lived and why they went extinct.
At that time, all life trolled the seas, and most of it was algae or bacteria. These strange, frondlike creatures looked a bit like ferns, with fractal branches radiating from a central, stemlike body. Some could be up to 6.5 feet high, though most were closer to 3.9 inches in length.