Dickinsonia were another Ediacaran marine oddity. Ranging from a few millimeters to 1.4 meters, Dickinsonia were a bilaterally symmetrical, ribbed, oval pancake. They grew by adding new rib-like segments.
Classifying Dickinsonia has been problematic. Proposals include that they were fungi, or some extinct kingdom. In 2018 paleontologists discovered that Dickinsonia produced cholesterol, “a hallmark of animals.”