Y.-Z. Wang prepared WS-30-R24. We thank R. Oâ€™Keefe, N. Fraser, and an anonymous reviewer for helpful advice and comments on the manuscript. Projects 40920124002 and 41372016 were supported by the National Natural Science Foundation of China. Project 123102 was supported by State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences). Project 20120001110072 was supported by the Research Fund for the Doctoral Program of Higher Education. D.Y.J. was supported by the Program for New Century Excellent Talents in University (NCET-07-0015). C.J. thanks F. Zheng (IVPP) for providing access to the holotype of Nothosaurus youngi.
Handling editor: Robin Oâ€™Keefe