Eight-armed Ediacara fossil preserved in contrasting taphonomic windows from China and Australia
- 11LPS, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
- 22South Australia Museum, North Terrace, Adelaide, South Australia 5000, Australia
- 33Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
- 44College of Resource and Environment Engineering, Guizhou University, Guiyang 550003, China
- 55Department of Earth Sciences, University of California, Riverside, California 92521, USA
Abstract
We report the preservation of the eight-armed Ediacara fossil Eoandromeda octobrachiata as carbonaceous compressions in the Doushantuo black shale of south China and as casts and molds in the Rawnsley Quartzite in South Australia. The contrasting preservational styles in two taphonomic windows indicate that E. octobrachiata may have had a relatively recalcitrant organic integument, which rules out its close comparison with giant agglutinated foraminifers such as xenophyophores. Its octaradial symmetry and dextrally spiraling arms suggest that it may be a diploblastic-grade animal sharing some features with cnidarians and ctenophores, although its phylogenetic affinity remains open. It is the first and only unambiguously identified Ediacaran macrofossil that occurs in two drastically different taphonomic windows, thus bridging the conventional biological and taxonomic gaps between the Ediacara and Miaohe biotas, which collectively record the earliest known macroscopic and complex life.
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- Received 27 May 2008.
- Revision received 18 July 2008.
- Accepted 27 July 2008.
- © 2008 Geological Society of America
