Molar tooth nomenclature of basal metatherian right M2 (upper) and left m2 (lower). Mesial is to the right, buccal is up. Teeth are based on the Late Cretaceous metatherian Glasbius.

  Part of: Williamson TE, Brusatte SL, Wilson GP (2014) The origin and early evolution of metatherian mammals: the Cretaceous record. ZooKeys 465: 1-76.