Fig. 4 in Muscle attachment scars in helcionelloids from Denmark cast light on mollusc evolution in the Cambrian

Fig. 4. Helcionelloid mollusc Eotebenna danica sp. nov., internal moulds, Andrarum Limestone, Bornholm, Denmark, Guzhangian, Miaolingian, middle Cambrian. A. MGUH 34277, lateral view (A1) with rectangles indicating location of Fig. 5B1, B2, and B3. Muscle scars at apex illustrated in different orientations (A2–A6), with arrow in A2 indicating slight diagenetic compression or deformation along edge of muscle field. Arrow in A3 indicating imbricated lamellar structure shown in detail in A4. B. MGUH 34278, apex in lateral view. C. MGUH 34279, lateral view. D. MGUH 34280, holotype, lateral (D1) and apico-lateral (D2) views, the latter showing the laterally compressed shell form, with detail of apical muscle scars (D3). E. MGUH 34281, lateral view. F. MGUH 34282, apex in lateral view. pontifex Runnegar and Jell, 1976, from the Currant Bush southern Freuchen Land, North Greenland is more strongly Limestone (Miaolingian) of Queensland, Australia, is also coiled than Eotebenna danica, with a convex supra-apical much more elongate than Eotebenna danica but the massive surface, in lateral view, and the apex strongly overhanging snorkel is circular in cross-section compared to the inverted the sub-apical surface (Peel 1989, 1991b). teardrop-shape in the two Bornholm species. Eotebenna arctica Peel, 1989, from the Henson Gletscher Stratigraphic and geographic range.—Drumian of Sweden Formation (uppermost Series 2, Stage 4, lower Cambrian) of and Guzhangian of Denmark (both middle Cambrian).