The dentition and relationships of the Paleocene primate Micromomys Szalay, with description of a new species

Abstract

Nearly complete lower dentitions (with c?, p2–4, m1–3) and the first discovered upper dentitions (with P2–4, M1–3) are described and illustrated for the late Paleocene primate Micromomys Szalay. These fossils, from the Paskapoo Formation of central Alberta, Canada, represent a new species, the geologically earliest known species of the genus. Micromomys appears to have been a primitive microsyopid most closely related to the early Paleocene Purgatorius Van Valen and Sloan and the middle Paleocene Palenochtha Gidley; a relationship between Micromomys and the early Eocene Tinimomys Szalay may not be as near as previous workers had supposed.Micromomys is the smallest primate known and was probably insectivorous. Its occurrence with the rare European primate Saxonella Russell, a new, primitive carpolestid, and an unusual mammal possibly related to palaeanodonts documents a facies not yet encountered in other Paleocene mammal local faunas, in Canada or elsewhere.