Fig. 52 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 52. Hyolith conchs from the lower Cambrian Erkeket Formation, Khorbusuonka River (C, D, F–H) and Tyuser (A, B) and Sekten (E) formations, lower reaches of the Lena River, Siberia, Russia; samples 19/12.75 (D, F, G), 19/25.5 (H), 19/33 (C), 21/51 (A, B), and 22/50 (E). A, B, D, F–H. Microcornus cf. eximius Duan, 1984, phosphatised conchs (A, B) and calcium phosphatic internal moulds (D, F, G), SMNH X11215–11220, respectively. C, E. Parkula bounites? Bengtson in Bengtson et al., 1990, phosphatised conchs, SMNH X11221–11222, respectively. B1, C2, D2, F3, oblique apertural, B2, C1, D1, F1, G1, dorsal; and D3, F2, G2, lateral views; E, enlargement showing inner surface of ventral side of a fragmentary conch. Scale bar: 500 µm (A–D, F–H) and 250 µm (E).