Rare patellogastropod limpets are described from the Cenomanian to Campanian (Cretaceous) age sediments in Hokkaido, northern Japan and Sakhalin, eastern Russia. Shell structure analysis has revealed the presence of five shell structure groups within six species, permitting the allocation of three of the species identified to modern clades. However, the other three species recorded belong to shell-structure groups not known at the present day. The species described in this paper are Patella soyaensis new species, Patella sp., Patelloida obirensis new species, ?Patelloida miyauchii new species, an indeterminate species of the Lottiinae, and an indeterminate species and belonging to an unknown family. Two species are recognized as belonging to the Patellidae and three species to the Lottiidae, demonstrating that two of the three major families found to inhabit present-day rocky shore environments already existed in the Cretaceous. The discovery of two Patella species belonging to a modern clade found in South Africa indicates that the fossil record of the clade dates back more than 80 Ma and the distribution of the clade has changed markedly since that time. The occurrence of Patelloida from the northwestern Pacific further elucidates the worldwide distribution for this genus during the Cretaceous.
Radiocarbon Marine Reservoir Ages in the Northwestern Pacific Off Hokkaido Island, Japan, During the Last Deglacial Period