New fossil deposits show complex animal groups predating the Cambrian

New fossils were described from the Jiangchuan site just south of Kunming near Fuxian Lake, in the Dengying Formation.

They come from a layer near the end of the Ediacaran period (Ediacaran ranged 635–540 million years ago), about 7 million years before the first clearly Cambrian deposits.

Specimens are small (typically 1–2 cm) and appear mostly as black, carbon-rich impressions in a single rock layer.

Some fossils preserve internal organs, showing exceptional soft-tissue preservation in places.

Researchers infer rapid burial in sediment in a shallow shore setting just deeper than low tide, an environment the team compares to Burgess Shale–type deposits.