Uppermost Jurassic (Volgian) rocks of the western Canadian Arctic Islands and northwestern mainland Canada contain rich faunas that include two oxytomid bivalves that are described as specifically and generically new: Canadotis canadensis n. gen., n. sp. and Arctotis (Canadarctotis) srugosa n. subgen., n. sp. The former is thought to be a derivative of an ancestral Meleagrinella-like Late Triassic or Early Jurassic bivalve; the latter is a development from mid-Jurassic Arctotis s.s. species. Both are important markers for the early Volgian in northern and northwestern Canada.