New species of Camptochlamys and Chlamys (Mollusca: Bivalvia: Pectinidae) from near the Cretaceous/Tertiary boundary at Ocean Point, North Slope, Alaska

Two new species of pectinid bivalves, Camptochlamys alaskensis and Chlamys aquilonia , are present in shallow-marine deposits near Ocean Point, northeastern Alaska, at about 70°N latitude. The precise age of these deposits is debatable, but paleontological and isotopic age estimates indicate placement near the Cretaceous–Tertiary boundary. The occurrence of Camptochlamys extends the chronostratigraphic and geographic range of this genus, previously unknown from any strata above the uppermost Jurassic (Tithonian) of Europe and unknown from any strata in North America. In contrast, the new Chlamys species represents an evolutionary advance beyond its nearest relative in the Maastrichtian of northern Europe and resembles Cenozoic members of its clade in certain features of shell microstructure. These new species are thus a microcosm of the debate regarding the age of these deposits and strengthen the hypothesis that the Ocean Point fauna lived in an Arctic Ocean basin that was isolated from the world ocean.