<i>Callorhinchus orientalis</i> sp. nov., a new callorhinchid from the Upper Cretaceous Hakobuchi Formation, Yezo Group, Hokkaido, Japan

Herein, we describe Callorhinchus orientalis sp. nov., an extinct callorhinchid chondrichthyan species found in the lower Maastrichtian deposits of the Hakobuchi Formation in Hobetsu, Hokkaido, northern Japan. This species is the first record of the genus Callorhinchus from the northern Pacific region, filling the biogeographical gap and implying survival beyond the Cretaceous/Paleogene extinction event because of the broad distribution of the genus. A comparison of Maastrichtian Callorhinchus species, including C. orientalis sp. nov., and Danian species indicates a potential period of temporal dwarfing within the genus across this extinction event.