Abstract
A new genus and species of erinaceid lipotyphlan (Mammalia, Insectivora) from the late Paleocene of western Canada is described. Oncocherus krishtalkai gen. et sp. nov. is known from three late Tiffanian localities in central Alberta and southeastern Saskatchewan and is but one of several erinaceomorph and soricomorph taxa known from the Late Paleocene of western Canada. Oncocherus possesses apomorphies that link it to other primitive erinaceids (e.g., enlarged upper and lower fourth premolars, lower molars markedly decreasing in size from m1–m3, talonid basins V-shaped), yet its affinity with any of the recognized erinaceid subfamilies is uncertain. Although Oncocherus is phenetically, and probably phylogenetically, closest to Litolestes Jepsen, the genus is clearly distinguished from Litolestes and other erinaceid taxa by its proportionately larger and more inflated premolars and lower crowned molars, features that were likely adaptations for durophagy. Oncocherus joins a number of endemic mammalian taxa that were apparently confined to more northerly latitudes of the Western Interior of North America during the Late Paleocene.