Fig. 4 in Conellae, enigmatic structures on cephalopod shells -shapes, distribution, and formation

Fig. 4. Sediment-filled conellae on phosphorite internal moulds of Late Oxfordian Amoeboceras serratum (Sowerby, 1813) (body chambers) from Rybaki locality in the Moscow region, Russia. A. GIN MPC 4/9, typical conella of tepee-like shape. B. GIN MPC 4/10, conella of more complex shape, note irregular outline. C. GIN MPC 4/11, groups of sediment-filled conellae with different heights. D. GIN MPC 4/12, shape of the neighbouring conellae differ significantly. E. GIN MPC 4/13, lateral view of a single conella. F. GIN MPC 4/14, conellae on the ventral keel (body chamber), with seemingly two growth phases and a lower conella in front.