Fig. 13 in The new stem-group brachiopod Oymurania from the lower Cambrian of Siberia

Fig. 13. Stem group-brachiopod Oymurania gravestocki Ushatinskaya gen. et sp. nov. from lower Cambrian Perekhod Formation, Achchagyi-Kyyry-Taas section, Siberia. Fragmentary shell with exfoliated surface (FUB AK21-018); apical (C), supra-apical (D), and upper (E) views; close-up of C showing lamellar wall (A), arrowed single chambers with acrotretoid columns situated within otherwise compact portion of the wall; close-up of D showing lamellae of the wall perforated by fine canals (B); close-up of D showing fine and coarser pores on the outer surface (F). Scale bar C–E, 1200 μm; A, 150 μm; F , 120 μm; B, 60 μm.