1. State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life & Environments Department of Geology Northwest University Xi’an 710069 China
2. Department of Biological Sciences Macquarie University Sydney NSW 2109 Australia
3. Institute of Earth Sciences, Palaeobiology Uppsala University SE‐752 36 Uppsala Sweden
4. Department of Palaeobiology Swedish Museum of Natural History Box 50007 SE‐104 05 Stockholm Sweden