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Gedinnian (Early Devonian) orthoceratid cephalopods were previously not well known in Japan. Five species are described from the Fukuji Formation of Gifu Prefecture, central Japan: Michelinoceras yamakoshii n. sp., Michelinoceras yoshikiense n. sp., Plagiostomaceras? sp., Polygrammoceras sp., and Metaspyroceras insignis n. sp. Growth and position of the cameral deposits in Michelinoceras indicate that the deposits precipitated from cameral fluids and living Michelinoceras maintained the shell horizontally in swimming orientation.

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