The Akiyoshi Limestone comprises an organic reef complex that was deposited on a seamount during Early Carboniferous to Middle Permian time. It is found as a large (8×16km across) allochthonous body in the accretionary Akiyoshi Terrane with synchronous siliceous and Permian terrigenous clastic sediments in Southwest Japan (Kanmera et al., 1990). The limestone is abundantly fossiliferous and provides knowledge of reef paleocommunities in a low-latitude oceanic sea environment. Taxonomic studies concerning the Akiyoshi cephalopod fauna began with Nishida (1971) and were followed by a series of works with his collaborators, including Nishida and Kyuma (1982, 1984), Kyuma and Nishida (1987, 1992), Niko et al. (1987, 1991). In the course of successive collecting efforts, twenty-nine specimens of a rare orthocerid cephalopod Bogoslovskya were recovered by Nishida and Kyuma from the Middle Carboniferous part of the Akiyoshi Limestone in the Isa area, Yamaguchi Prefecture. A new species Bogoslovskya akiyoshiensis is defined herein on the basis of these specimens. ASM stands for the Akiyoshi-dai Museum of Natural History.
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