ACKNOWLEDGEMENTS
This work was supported by the National Natural Science Foundation of China (31470312; 31470319; 31970231), Science and Technology Planning Project of Guangdong Province, China (2016A030303048). We thank Xiaolan Wang, Juan Zhou, Bo Li, Yemei Huang, and Zhong Zhang for help with sampling and field trips. We thank Zhixia Sun, Mark Ravinet, Joana Meier, Tongjian Liu, Huiqin Yi, and Haifei Yan for data analyses. Special thank goes to Prof. Qi Wang for providing fossil information.