The Ediacaran Period is the geological period from 635 to 541 million years ago which follows the Precambrian supereon and precedes the Cambrian Period, characterized by the sudden appearance of soft-bodied multicellular organisms in the fossil record. The Ediacaran Period is named after the Ediacara Hills of South Australia, where fossils of these organisms were first found.
The Ediacaran biota consisted of enigmatic tubular and frond-shaped, mostly sessile organism that lived during the final stages of Earth’s Proterozoic Eon (approximately 2.5 billion to 541 million years ago). Trace fossils of these organisms have been found worldwide, and represent some of the earliest known complex life forms on Earth.
Although often referred to as “animals”, they are now thought to represent a separate domain or possibly multiple domains given their range of body plans. Their odd appearance, unknown mode(s) of locomotion (if any), and lack of certain key features such as eyes and mouths has made it difficult to determine their place in the tree of life; however, they may be related to modern cnidarians (e.g., jellyfish, anemones), ctenophores (comb jellies), or other groups.
The simplest explanation for this apparent paradox is that either these animals had a brief reign at or near the dawn of animal life on Earth, but left few if any descendants that survived into later periods; alternatively, they may not have been animals at all but rather something else entirely such as lichen-like symbiotic colonies or early plants. It is also possible that some or all members of this group were related to animals alive today but went extinct prior to the start of the Cambrian period without leaving any direct descendants..