Fig. 2

Population delimitation of Beesia (a-g) and Megacodon (h-m). (a-c) Genetic structure of Beesia based on, respectively, K = 2–4 for dataset B119. (d-e) PCA analysis based on dataset B119. (f), geographic distribution of genetic structure of Beesia based on K = 4. Dashed circles in (f) encompass groups inferred by STRUCTURE. A representative leaf from each Beesia group is shown. (h) Genetic structure of Megacodon based on K = 2 for dataset M155. (i) and (j) are genetic structure based on, respectively, K = 2 and K = 3 for dataset M131. (k) PCA analysis based on dataset M155 (outer) and M131 (inner). (l), geographic distribution of genetic structure of Megacodon based on K = 4 for dataset M155. A representative flower from each Megacodon species is shown. Dashed circles in (l) encompass groups of M. stylophorus inferred by STRUCTURE at K = 4. Schematic views of altitudinal distribution of genetic structure and phylogenetic relationships of Beesia (g) and Megacodon (m). Genetic structure for Beesia in (g) were inferred from B119 dataset. Orange dashed line and numbers in (g) show the elevation of BC_HM (> 2700 m) and BC_SC groups (1800–2200 m). Genetic structure for Megacodon in (m) were inferred from M155 datasets. Blue dashed lines and numbers in (m) show elevation of M. stylophorus (> 3690 m), M. lushuiensis (1700 m) and M. venosus (1100 m). Phylogenetic trees at bottom are simplified versions from BEAST results presented in Fig. 1. The estimated geographic regions of occurrence are estimated by BioGeoBEARS. Pie charts in (g) and (m) on nodes represent the relative probabilities of occurrence areas for the Beesia and Megacodon corresponding to (f) and (l) respectively. Reconstructions resulting in more than two possible regions are shown in dark gray. EH, East Himalayas; HM, Hengduan Mountains; Basin: Sichuan Basin; black dashed line: mountains around Sichuan Basin