Fossil site in China shows complex creatures lived before the Cambrian explosion

A fossil deposit from the Jiangchuan Biota in southwestern China has yielded more than 700 carbonaceous film fossils dated about 554–539 million years ago, showing diverse soft-bodied animals present before the Cambrian explosion.

A newly reported fossil deposit in southwestern China, part of the Jiangchuan Biota, contains more than 700 specimens dated to roughly 554–539 million years ago. The fossils are mainly carbonaceous films that preserve traces of soft tissues rather than hard parts. The collection includes bilateral worm-like animals that may have anchored to the seafloor, early comb jellies, and relatives of starfish and sea cucumbers, along with other forms that do not closely match known Ediacaran or Cambrian species. Study authors say these fossils indicate a wider range of complex animal forms existed before the traditional start of the Cambrian explosion. Key findings: - The site yielded more than 700 fossil specimens from the late Ediacaran period, dated between about 554 million and 539 million years ago. - Most specimens are preserved as carbonaceous films, a preservation mode that can record soft tissues such as guts and mouthparts. - Identified forms include bilateral worm-like organisms, early comb jellies, and echinoderm relatives that likely used head tentacles to capture food. - Some fossils do not resemble known Ediacaran or Cambrian taxa, indicating previously unrecognized morphologies. - Study co-author Frankie Dunn is reported as saying one specimen looks similar to the sandworm from Dune, a descriptive comparison noted by the researchers. - Authors suggest the apparent absence of similar complex groups at other sites may reflect differences in preservation rather than true biological absence. Summary: The discovery expands the known diversity of late Ediacaran life and indicates some complex animal forms were present several million years before the Cambrian explosion. Undetermined at this time.