The Ediacara biota (580–541million years old) marks the first appearance of macroscopic and architecturally complex organisms in Earth history. Although Ediacara fossils have been known from nearly 30 localities on all major continents except Antarctica, they are almost exclusively preserved in sandstones. A new discovery, announced recently in Scientific Reportsby scientists from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and the Department of Geosciences at Virginia Tech, shows that some classical elements of the Ediacarabiota could live in carbonate environments and can be preserved in marine limestones. The new fossils will fundamentally change the ecology and preservation of Ediacara fossils.
Ediacara fossils predate the massive radiation of animals during the Cambrian Explosion (541–520 million years ago). Thus, they have the potential to illuminate the prelude to the Cambrian Explosion. However, these fossils are open to wide speculations. Some scientists believe that the Ediacara biota includes marine animals representing the precursors to the Cambrian Explosion, whereas others see Ediacara fossils as lichens living on land. The new fossils were discovered from the ~550 million-year-old Dengying Formation in the Yangtze Gorges area, and include several widespread Ediacara elements such as Hiemalora, Pteridinium, Rangea, and Charniodiscus, as well as a new annulated tubular fossil that was named Wutubusannularis after Wuhe, a village close to the fossil discovery site. The new fossils significantly expand the geographic, stratigraphic, environmental, and taphonomic distribution of some key Ediacara elements. Their occurrence in marine limestone of the Dengying Formation also suggests that these Ediacara taxa were not lichens living on land. Instead, they were marine organisms living a subaqueous life. Whether they are animals, animal precursors, or distant relatives of animals is still unknown.
This research was supported by Chinese Ministry of Science and Technology, National Natural Science Foundation of China, Chinese Academy of Sciences, and U.S. National Science Foundation.
Related information of this paper: Zhe Chen, Chuanming Zhou, Shuhai Xiao, Wei Wang, Chengguo Guan, Hong Hua, Xunlai Yuan, 2014, New Ediacara fossils preserved in marine limestone and their ecological implications. Scientific Reports, 4: 4180. DOI: 10.1038/srep04180
Ediacara fossils from Dengying Formation in the Yangtze Gorges area
Wutubusannularis
(Information Source: Nanging Institute of Geology and paleontology, CAS)
