Fig. 2From: Hyolithid-like hyoliths without helens from the early Cambrian of South China, and their implications for the evolution of hyolithsParamicrocornus ventricosus preserved with some structures on the operculum from the Chengjiang Biota. A ELI-H-EJ186A. Complete specimens preserved in three-dimensions in dorsal view. B ELI-H-EJ186A. One partly buried individual covered by another animal, showing the deep sulcus between conical and cardinal shields filled with mud, and a circular pit on the summit of the conical shield. C ELI-H-EJ186B. Enlarged view of the counterpart of B. D SJZ-242. Conch with sharp apex and short ligula on venter. E, F ELI-H-EJ186B. E Articulated specimen showing the clavicles on operculum interior. F Close-up view of blade-like clavicles with parallel ridges representing clavicle rods. H Reconstruction of P. ventricosus. G SJZ-B08-509B.I Individual of P. ventricosus with clavicles on the internal surface of operculum marked by arrows. I SJZ-B08-509B. Three-dimensionally preserved specimen in dorsal view with triangular operculum. J SJZ-B08-509A. Aggregation of P. ventricosus. K SJZ-B04-033. Two conchs of P. ventricosus with sharp apex, L SJZ-B04-033. On articulated specimen showing the very sharp apex with a linear internal tube towards the pointed conch apexBack to article page