Pediomys krejcii
Marsupial
Late Cretaceous (Maastrichtian)
Hell Creek Formation
Harding County, South Dakota, USA

15mm jaw section with three teeth of a primitive marsupial mammal.

Pediomys is a genus of extinct small to medium-sized marsupial known from the Late Cretaceous of North America. It’s weird but true that marsupials appear to have evolved in western North America in the Early Cretaceous, spreading to other continents later. Pediomys died out during the end-Cretaceous mass extinction along with most other marsupials.

Substantial section of jaw with teeth and alveoli showing were other teeth were present. Some collectors love the specimens they can look at under a microscope.