Fig. 4From: Geological history of the land area between Okinawa Jima and Miyako Jima of the Ryukyu Islands, Japan, and its phylogeographical significance for the terrestrial organisms of these and adjacent islandsStratigraphic succession of limestones within the Ryukyu Group. Schematic figure showing stratigraphic succession and the spatial arrangement of limestones within the Ryukyu Group (modified from Yamamoto et al. 2006). Cy.-Op., Cycloclypeus-OperculinaBack to article page