Fig. 20 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 20. Stem-group Brachiopoda indet. from the lower Cambrian Erkeket Formation, Khorbusuonka River, Siberia, Russia; sample 20/1B. Fragments of shell, SMNH X11001 (A) and SMNH X11002 (B). A1, B2, general view; A3, A4, close-ups showing prismatic walls and openings of presumably setigerous canals; B1, enlargement showing prismatic wall. Scale bar: 500 µm (A1, A2, B2), 125 µm (A4, B1), and 50 µm (A3).