| Popis: |
A float block of Mesozoic conglomerate, probably derived from the Lower Jurassic Kuruma Group, containing Devonian tabulate corals was collected in the Kotaki area, Itoigawa, Niigata Prefecture, central Japan. As the first fascicle of our study concerning this material, the present paper focuses on taxa of the suborder Favositina. They consist of Favosites? sp. indet., Pachyfavosites sp. indet. 1, P. sp. indet. 2, Plicatomurus? sp. indet., Thamnopora itoae Niko, Ibaraki and Tazawa sp. nov. and Thamnoptychia mana Niko and Senzai, 2010 from milky white to gray limestone pebbles and Hillaepora sp. indet., from black shale pebble. A Givetian (late Middle Devonian) species, Thamnopora nicholsoni (Frech, 1885), shows close resemblance with the new species, but differs by having larger mean diameters of the distal corallites and the fewer tabulae. Thamnoptychia mana indicates a Givetian age. Reliable stratigraphic distribution of the genus Hillaepora is restricted within the Lower Devonian. |
