Avalon explosion

[3] This evolutionary event is believed to have occurred some 33 million years earlier than the Cambrian explosion, which had been long thought to be when complex life started on Earth.

Scientists are still unsure of the full extent behind the development of the Avalon explosion,[3] which resulted in a rapid increase in metazoan biodiversity, including the first appearance of some extant infrakingdoms/superphyla such as cnidarians and bilaterians.

[3] Charles Darwin predicted a time of ecological growth before the Cambrian Period, but there was no evidence to support it until the Avalon explosion was proposed in 2008 by Virginia Tech paleontologists after analysis of the morphological space change in several Ediacaran assemblages.

There were over 270 species defined,[10] with 50 different morphological characteristics categories, many of whose anatomical structures had to be inferred with fossils and casts.

[11] Animals at this time developed bilateral symmetry with a clear anterior and posterior side, which included species like Spriggina, Charniodiscus and Yorgia.

Dickinsonia , an enigmatic quilted organism with glide symmetry which may have been an early animal
Cloudina may have been one of the first mineralized animals to appear, although its life appearance and evolutionary affinities remain unknown. [ 1 ]
Kimberella was originally interpreted as a cubozoan cnidarian , although it is now believed it was an early mollusc. [ 2 ]
The Ediacaran trace fossils are a sign of animal movement as well as sediment disturbance, they show possible signs of the earliest true animals.