Fig. 40 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 40. Hyolith conchs from the lower Cambrian Erkeket Formation, Khorbusuonka River (A–D, G, H, K–N) and Tyuser Formation, lower reaches of the Lena River (E, F, I, J), Siberia, Russia; samples 11/16.05 (K), 11/16.1 (A), 11/16.5 (B, C), 11/2B (D), 19/4.25 (H), 19/11.75 (L), 19/12.75 (M, N), 19/14.25 (G), 21/21 (I, J), and 21/51 (E, F). A, B. Conotheca mammilata Missarzhevsky in Rozanov et al., 1969, phosphatised conchs, SMNH X11136 and 11137, respectively. C, D. Conotheca mammilata Missarzhevsky in Rozanov et al., 1969, phosphatised conchs with initial part preserved, SMNH X11138 and 11139, respectively. E, F. Conotheca cf. longiconica (Qian, 1978), phosphatised conchs, SMNH X11142 and 11143, respectively. G, H. Conotheca circumflexa Missarzhevsky in Rozanov et al., 1969, phosphatised conchs, SMNH X11140 and 11141, respectively. H2, close-up showing transversal fibers in the wall. I–K. Egdetheca aldanica Missarzhevsky in Rozanov et al., 1969, calcium phosphatic internal moulds, SMNH X11144–11146, respectively. K1, lateral view; K2, apical view. L–N. Orthothecida sp. indet., calcium phosphatic internal moulds, SMNH X11147–11149, respectively. M1, lateral view; M2, dorsal view. Scale bar: 1 mm (A), 500 µm (B–D, G–K), 250 µm (E, F, L–N), and 50 µm (H2).