Revision of the orbitolinid foraminiferal genus Praeorbitolinoides Matsumaru 2005 from the Aptian of Hokkaido, Japan

A revision of Praeorbitolinoides japonica, established by Matsumaru (2005) as new genus and species from the Aptian of Hokkaido (Japan), reveals that this taxon is identical with transitional forms between Praeorbitolina cormyi and P. wienandsi Schroeder 1964 known from the upper part of the early Aptian (Deshayesites deshayesi and Dufrenoyiafurcata ammonite Zones) of the Tethyan realm. Praeorbitolina gr. cormyi-wienandsi and possibly Palorbitolina lenticularis represent at present the oldest orbitolinids found in Japan. The former genus is reported for the first time from the circum-North Pacific regions.