Fig. 32. Problematic shell 2 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 32. Problematic shell 2, from the lower Cambrian Erkeket Formation, Khorbusuonka River, Siberia, Russia; samples 19/11.75 (A–C, E) and 19/10.25 (D). A–E. Phosphatised fragments of shells with spines, SMNH X11039–11043, respectively. A1, D1, plain view; A2, lateral view of the shell fragment with cyanobacterial filaments (SMNH X11337, see Fig. 69A) attached to its inner side (bottom); A3, close-up showing spines; D2, lateral view. C, E, fragments of presumably subapical part of the shell. E1, E2, view on the same fragment, ca 90º rotated around the longitudinal axis. Scale bar: 250 µm (C, E), 165 µm (A1, A2, B1, D), and 50 µm (A3, B2).