Known also as the Vendian, the Ediacaran was the final stage of Pre-Cambrian time. All life in the Ediacaran was soft-bodied - there were no bones, shells, teeth or other hard parts. As soft bodies don't fossilise very well, remains from this period are rare. The world's first ever burrowing animals evolved in the Ediacaran, though we don't know what they looked like. The only fossils that have been found are of the burrows themselves, not the creatures that made them. This period gets its name from the Ediacara Hills in Australia, where famous fossils of this age were found.

Began:635 million years ago

Ended:545 million years ago

Variations of Ediacaran Morphology

The branching morphology of Ediacaran rangeomorph fronds has no exact counterpart in other complex macroorganisms suggesting they form a distinct phyllum possibly lying between the sponges and other animals. The fractal body plan of rangeomorphs is shown to maximize surface area, consistent with diffusive nutrient uptake from the water column (osmotrophy), optimized for unique ecological and geochemical conditions in the late Proterozoic. The appearance of rangeomorph fossils (1) occurred after a move away from anoxic, sulfidic, and ferruginous oceans, toward conditions more favorable for aerobic macroorganisms. At the Cambrian explosion, the ecological and geochemical conditions to which the rangeomorphs were optimized ceased to exist, and their extraordinary body plan was lost from life's repertoire.

Jennifer F. Hoyal Cuthill and Simon Conway Morris 2018 Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan doi/10.1073/pnas.1408542111,

Fig 23b2 (a) Dicksonia (b) Sprigginia (c) Yilingia (d) Charnia. Sprigginia and Yilingia (doi:10.1038/s41586-019-1522-7) show bilateral segmented structure characteristic of early bilateran organisms leading to annelids, arthropods and vertebrates, while Dicksonia shows the quilted form of many enigmatic Ediacarian fossils.