Description

Late Cretaceous (Maastrichtian)

Hell Creek Formation

Harding County, South Dakota, USA

Excellent 7mm jaw section with very fine p3 and molar

Mammal, Multituberculate.

Mesodma is a genus of the Order Multituberculata, a branch of Jurassic-Eocene mammals entirely separate from any mammal groups that live today.  They would have resembled rodents and probably had much the same lifestyle but they had a different dentition as seen especially in the shape of the lower third premolar (preserved in this specimen).  Mesodma was one of the multituberculates that survived into the Early Paleocene after the K/T mass extinction.