FIGURE 1. Locality and stratigraphy of the Cambrian (Terreneuvian) Yanjiahe Formation in Yichang, Hubei Province, China. 1. Sketch map of the People’s Republic of China, showing the position of the collecting locality in Hubei Province; 2. Simplified geological sketch map of the Three Gorges area, Hubei Province, South China, showing the outcrops of Cambrian strata. Red boxes around 3 (Yanjiahe area) and 4 (Dingjiaping area) denote areas that are enlarged for additional detail; 3. Detailed geological sketch map of the Yanjiahe area, showing the outcrops of the Yanjiahe Formation; 4. Detailed geological sketch map of the Dingjiaping area, showing the outcrops of the Yanjiahe Formation. (In 3 and 4 map: White = Ediacaran Dengying Formation; Pink and light green = Cambrian Yanjiahe Formation; Yellow and light blue = the Cambrian Shuijingtuo Formation; Green = Cambrian Shipai Formation; Black triangles indicate locations of measured stratigraphic sections) 5. Stratigraphic sequence of Lower Cambrian strata in the Gunziao section, Three Gorge area, indicating the horizons where fossils were collected.
FIGURE 2. Protoconites minor from the Cambrian (Terreneuvian) Yanjiahe Formation in Yichang, Hubei, China. 1. No. Y-24B (2); 2. No. Y-41A (5)-1; 3. No. Y-765A (3); 4. No. Y-127B (1); 5. No. Y-28 (2); 6. No. CH-179A (3); 7. No. Y-273A (1); 8. No. Y-41A (14); 9. No. Y-445 (2); 10. No. Y-494 (2)-2; 11. No. Y-40A (11); 12. No. Y-1234 (3); 13. No. Y-844A (2); 14. No. Y-785 (2); 15. No. Y-40B (9)-1; 16. No. Y-880 (6); 17. No. Y-596 (2)-1; 18. No. Y-531 (3)-2. “CH” means the locality of the fossils from Dingjiaping section, “Y” means the locality of the fossils from Yangjiachong section.
FIGURE 3. Definition of landmarks and semi-landmarks and the result of superimposition. 1. and 2. landmarks and semi-landmarks set on both straight and laterally bent specimens. Type II landmarks are 1, 2, and 3, and sliding semilandmarks are 4-34 in 1. and 2.; 3. consensus configuration after superimposition using Generalized Procrustes Analysis.
FIGURE 4. Histogram showing the size spectra of Protoconites minor. 1. size distribution of all specimens analyzed in this study; 2. size distribution without laterally bended specimens.
FIGURE 5. Protoconites minor morphospace generated by the Relative Warp (RW) analysis using un-mirrored specimens with indication of characteristic thin-plate splines. 1. plot for RW 1-2; 2. plot for RW 1-3. Thin-plate splines show the shapes of specimens in RW 1-2 and RW 1-3 planes, respectively.
FIGURE 6. Protoconites minor morphospace generated by the Relative Warp (RW) analysis using mirrored specimens. 1. plot for RW 1-2; 2. plot for RW 1-3. All thin-plate splines correspond to points (indicated as a line) within the morphospace in RW 1-2 and RW 1-3 planes, respectively.
FIGURE 7. Morphospace of straight shell Protoconites minor generated by the Relative Warp (RW) analysis. 1. plot for RW 1-2; 2. plot for RW 1-3. All thin-plate splines correspond to the shapes of specimens in RW 1-2 and RW 1-3 planes, respectively.
FIGURE 8. The ordinary least-squares linear regression of the shape of mirrored Protoconites minor with log10- transformed centroid size. Characteristic specimens are shown in thin-plate splines corresponding to the shapes of specimens in RW 1-2 plane.
FIGURE 9. The ordinary least-squares linear regression of the shape of straight-shelled Protoconites minor with log10 - transformed centroid size. Characteristic specimens are shown in thin-plate splines corresponding to the shapes of specimens in RW 1-2 plane.
FIGURE 10. Protoconites minor from the Cambrian (Terreneuvian) Yanjiahe Formation showing morphological variance during the ontogeny. Size of these specimens increases from right to left and from top to bottom. 1. No. Y-596 (2)-2; 2. No. Y-735A (20)-2; 3. No. Y-800A (19)-2; 4. No. Y-469B (5); 5. No. Y-581 (2); 6. No. Y-134 (10); 7. No. Y-523; 8. No. Y-1236 (2); 9. No. Y-29; 10. No. Y-617A (4)-3; 11. No. Y-558A (17); 12. No. Y-141A (19)-1; 13. No. Y-558A (33); 14. No. Y-617A (2); 15. No. Y-546A (2); 16. No. Y-732A (20); 17. No. Y-142A (8)-1; 18. No. Y-816A (4); 19. No. Y-1230A (45); 20. No. Y-425A (2); 21. No. Y-561A (5); 22. No. Y-567 (2); 23. No. Y-732A (32)-1; 24. No. Y-173A (4); 25. No. Y-1227A (10); 26. No. Y-51A (2); 27. No. Y-24B (2). “Y” means the locality of the fossils from Yangjiachong section.
