1. Department of Biological Sciences Macquarie University North Ryde Sydney NSW 2109 Australia
2. Department of Earth Sciences, Palaeobiology Uppsala University Villavägen 16 Uppsala SE‐75236 Sweden
3. Department of Palaeobiology Swedish Museum of Natural History Box 50007 Stockholm SE‐10405 Sweden
4. State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments & Department of Geology Northwest University Xi'an 710069 China
5. State Key Laboratory of Palaeobiology & Stratigraphy & Centre for Excellence in Life & Paleoenvironment Nanjing Institute of Geology & Palaeontology Chinese Academy of Sciences Nanjing 210008 China
6. University of Science & Technology of China Hefei 230026 China
7. Department of Geology Colorado College Colorado Springs CO 80903 USA