2018 Volume 124 Issue 11 Pages 913-918
A Permian brachiopod species, Leptodus nobilis, is identified for the first time in argillaceous limestone boulders within the basal conglomerate of the Pliocene Kume Formation, Hitachi area, central Japan, and added to the Ishinazaka fauna. This fauna, consisting of 18 species in 17 genera, is assigned to the Wordian stage (middle Permian). In terms of palaeobiogeography, the Ishinazaka fauna has a close affinity with the middle Permian brachiopod faunas of northeastern Japan (South Kitakami Belt), eastern Russia (South Primorye), and northern China (Inner Mongolia). The fossil-bearing boulders were probably derived from the Ayukawa Formation within the Hitachi Palaeozoic rocks. Therefore, the Hitachi area was probably part of a continental shelf situated along the eastern margin of North China (Sino-Korea) during the Wordian, and the Ayukawa Formation belongs to the South Kitakami Belt, northeastern Japan.
