The Marginatia-Syringothyris-Rotaia brachiopod assemblage from the Lower Carboniferous of the South Kitakami Belt, northeast Japan, and its palaeobiogeographical implications

Abstract

Three brachiopod species, Marginatia burlingtonensis (Hall), Syringothyris transversa Minato and Rotaia hikoroichiensis sp. nov., are described from the Lower Carboniferous (Lower Visean) of the Shimoarisu, Yokota and Hikoroichi areas in the South Kitakami Belt (southern Kitakami Mountains), northeast Japan. The Marginatia-Syringothyris-Rotaia assemblage from the South Kitakami Belt indicates a palaeobiogeographical similarity between the South Kitakami Belt and the north Xinjiang-Inner Mongolia-Jilin region, i.e., the North China Province of S. Yang (1980) in Early Carboniferous time. Furthermore, the rugose corals Sugiyamaella, Yuanophyllum and Kueichouphyllum from the Lower Carboniferous (Upper Visean) of the South Kitakami Belt are strong evidence of a close connection between this region and the southern part of the North China Province, i.e., the Tianshan-Jilin Province of F. Yang (1994). These palaeobiogeographical data suggest that the South Kitakami region was the eastern extension of the Tianshan-Jilin Province, and located at the continental shelf bordering the eastern margin of North China (Sino-Korea) in the Early Carboniferous.