A peculiar new fossil shrew (Lipotyphla, Soricidae) from the High Arctic of Canada

Abstract

Arctisorex polaris, gen.n., sp.n., from the late Neogene of Ellesmere Island, Nunavut, is the most northerly record thus far of a shrew. The genus is represented by the posterior moiety of a dentary and last two molars. The well-developed M₃ and the extreme distance between the articular condyles, separated by a narrow interarticular isthmus, agrees best with the neomyine shrews. The expansion and anterior inclination of the coronoid process, extreme elongation of the third molar that results in it being longer than the M₂, and the M₃ with a distinct entoconid valley, are unique among soricids. We suggest that Arctisorex may be the only shrew specialized for frugivory.