AUTHOR CONTRIBUTIONS
Y.X.L., S.L. and F.Z. conceived and designed the project. W.J.C., C.W.H. and A.M.L. prepared samples for sequencing. C.W.H., M.P. and Y.B. performed morphological studies. F.Z., Y.X.L., Y.C, J.F.J., W.J.C. and A.M.L. performed data analyses. Y.X.L., F.Z., Y.C. and W.J.C. wrote the manuscript. S.L. and S.Z. provided critical revisions. All authors read and approved the final manuscript.