Kasimovian (Late Pennsylvanian) conodont fauna from a limestone block in the Ōtani Formation, Kuzuryu area of the Hida Gaien belt, Fukui Prefecture, central Japan

Abstract

A conodont fauna characterized by Streptognathodus species was recovered from a limestone block (previously called Ōboradani Formation) of the Ōtani (=Ohtani or Otani) Formation belonging to the Hida Gaien belt distributed in the Kuzuryu area, Fukui Prefecture, central Japan. The fauna consists of Streptognathodus corrugatus, S. elegantulus, S. excelsus, S. gracilis, Idiognathodus sp., Gondolella bella, G. cf. elegantula and G. cf. pohli. These streptognathodids have a wide geographic distribution and indicate a middle-late Kasimovian (Late Pennsylvanian) age, which is slightly older than the Gzhelian (latest Pennsylvanian) age infferred from fusulinid fossils in previous studies. Thus, the limestone block of the Ōtani Formation probably contains the Upper Pennsylvanian carbonate succession.