Online supporting material: †Estelestes ensis (Mammalia, Metatheria) from the Early Eocene of Baja California, Mexico, as a generalized polydolopimorphian

In Table 1, we provide the ratio between the length of m1-4 and the height of the dentary below m1 in several extinct and extant metatherians from the Americas. We give the taxonomic assignment (Family, Order) for each of the measured species and indicate the source of the figure where the ratio was obtained. In Figure 1, we show details of the anterior portion of the left lower jaw of Bobbschaefferia fluminensis (MNRJ 1350-V, cast of the holotype) in occluso-lateral and occlusal views.