Extended Data Figure 2: C. kroegeri YPM 227515, paratype.

a, Part, illuminated from the northwest. b, Counterpart, illuminated from the southwest and then mirrored horizontally. c, Interpretative drawing of YPM 227515 with part and counterpart combined. Interpretations below the stippled line are derived from the counterpart. Boxes denote position of details shown in d, e, g. Areas shown in green are of the exposed ventral mantle, areas within dashed lines denote gaps in preservation, dark blue shows the teeth of the radula and light blue denotes the shell. Sclerites are shown in orange but are only drawn where lying flat or covering the shell. d, Exposed ventral mantle, which is preserved in darker colouration but shows no visible sclerites. e, Folded dorsal mantle which preserves dorsal sclerites in longitudinal section. Boxed area is magnified in f. f, Dorsal sclerites. g, Dorsal sclerites in cross-section and marginal sclerites in longitudinal section.