The authors thank all colleagues who have participated in the Lantian Project, Dr. L. Liu and Mr. W. Zhou for the Fugu field season, and Mr. Q. Hao for providing generously the Qin'an fossil. Research for this paper was supported financially by the Ministry of Science and Technology of China (G2000077707, G2002CB714002), Natural Science Foundation of China (40272009), and Academy of Finland (44026). The authors thank Dr. S. Sen for providing access to fossil spalacids from Turkey. We all benefited from discussions with W. Downs, who was intensely interested in the Lantian project and promoted open sharing of information on Chinese fossil data sets.