Fig. 63 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 63. Echinoderm plates from the lower Cambrian, Erkeket Formation, Khorbusuonka River, Siberia, Russia; samples 19/10.25 (A, B), 19/11.75 (E, G–I), 19/12.75 (C, F), 19/25.5 (J, L), 20/2B (K), and 20/6B (D, M). A, B. Proximal stem plates of Rhombifera, SMNH Ec36873 and 36874, respectively. C–G. Edrioasteroid thecal plates (from basal attachment disc?), SMNH Ec36876–36880, respectively. H. Plate from edrioasteroid mouth-frame, SMNH Ec36881. I. Ambulacral flooring plate of Edrioasteroidea, SMNH Ec36875. I1, oblique view, a shallow pit for presumably insertion of a ligament for a cover-plate is arrowed; I2, upper view. J–L. Ctenidial plates (Echinodermata, Ctenocystoidea), SMNH Ec36882–36884. K1, plain view on a trapezoidal dorsal blade; K2, plain view of the plate showing dorsal blade and hook-shaped process; K3, plate in lateral view. M. Echinodermata, thecal frame-plate of unknown affinity, SMNH Ec36885. Scale bar: 1 mm (D, F, I, M) and 500 µm (A–C, E, G, H, J–L).