FIGURE 3. Comparison of (A) the reconstructed wall of Archaeochionelasmus nekvasilovae gen. et sp. nov. with (B) an illustration of a juvenile of Chionelasmus ohtai having the first whorl of basal imbricating plates (from a line drawing by D.S. Jones, with permission in litt. 2016), and (C) an adult of Chionelasmus ohtai; CL overlaps the ala of C, as is indicated on left side, whereas CL abuts rather than overlaps R (Yamaguchi & Newman 1990, fig. 8B), their articulation being strengthened and protected by the addition of the RL applied over the abutment of CL and R, dividing SRL into more or less equal halves.