Fig. 11

Comparison between the tabulate corals Aulopora and Catenipora. a Longitudinal section of Catenipora, consisting of tubes with tabulae and fence-like arrangement; b Cross section of Catenipora; c Three-dimensional view of Catenipora, composed of tubes arranged in a fence forming mesh-like structure; d Longitudinal section of Catenipora, showing the laminofibrous microstructure of the tube walls composed of fiber calcite slightly oblique to tube surface; e Detailed view of the red box in Fig. 11d. Note the tube wall displaying laminofibrous microstructure; f One cross section and two oblique sections of Aulopora, displaying round and oval forms with diameters of 0.2–0.3 mm. The tube walls exhibit laminofibrous (fibronormal) microstructure and have average thickness of about 30 μm, with tabulae in the oblique sections; g Enlargement of the red box in Fig. 11f; h Longitudinal section of Aulopora; i) Enlargement of the red box in Fig. 11h. a-e were from the Upper Ordovician Sanqushan Formation in Yushan area, Jiangxi Province; f-i were from the Lower Devonian Sipai Formation of Xiangzhou area, Guangxi Province