A peculiar type of fossil from the Precambrian era, before the "Cambrian explosion" that spawned modern life¹. Named for the first major discovery site in the Ediacara Hills of south Australia, but found in many parts of the world in 600 million year old rock. An excellent field is at Mistaken Point in Newfoundland. Usually they are found in layers of volcanic ash or other strata laid down by quick, violent action. There are no hard parts in Ediacaran fossils, so they are only found in circumstances that entombed them before they could decay.
They are a mystery to science because they defy our standard classifications of biota. They have complex form, with various shapes and creases or branches. However, with no indication of heads, tails, muscles, organs, circulatory or digestive systems, they seem to be more like an air mattress than any known form of life. Many of the fossil types defy our understanding and classification systems. Some scientists theorize that they used photosynthetic symbiosis in a way simialr to modern corals.
They disappeared around the start of the time of the Cambrian, scientists disagree about why. Some think the Ediacarans may be our remote ancestors, but most feel that they were an evolutionary dead end that vanished before our own branch of life began.
Also known as the Vendobiota or Vendobionta.
Also, the last geologic period in the Precambrian age, at the end of the Neoproterozoic Era, 542-600 million years ago. Known to Russian geologists as the Vendian period, the Ediacaran name was recently (2004) given official status by the International Commission on Stratigraphy (ICS) and the International Union of Geological Sciences (IUGS).
1. With apologies to theonomist.