The brown lemming, Lemmus sibiricus (Rodentia, Arvicolidae), in the late Pleistocene of Alberta and its postglacial dispersal

Abstract

The first fossil remains of Lemmus sibiricus south of Beringia are reported from a rock shelter called January Cave in the Front Ranges of the Rocky Mountains, southwestern Alberta, Canada. The 45 specimens were excavated along with several thousands of isolated small mammal teeth and fragmentary bones. Dated by both radiocarbon and thermoluminescence methods to span the last 22 000 – 23 000 years, a late Pleistocene-through-present sequence is provided. Argument is made for the existence of a southern relict population of this lemming prior to a northward, postglacial dispersal into British Columbia and the Yukon Territory.