1. Paleontological Museum of Liaoning, Shenyang Normal University, Shenyang Liaoning 110034, China.
2. College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, China.
3. Department of Geology and Geophysics and Peabody Museum of Natural History, Yale University, New Haven, CT 06511, USA.
4. Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637, USA.
5. Section Paleontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany.