In light of the findings of Wible et al. (2007), we might even doubt whether many of the Palaeocene eutherians even represent placentals. The classification of McKenna and Bell (1997) united many early eutherians such as Cimolestidae, Pantodonta and Taeniodonta (as well as the modern pangolins) into a group called Cimolesta, which was then included in the Ferae with creodonts and Carnivora. While pangolins may indeed be related to carnivorans, Cimolestidae, as referred to above, are not even placentals. What then becomes of the rest of the "Cimolesta"? Are they also stem-eutherians like Cimolestidae, or are they true placentals?
Such questions are not mere curiosities - the answer could have significant effects on our understanding of Palaeocene ecology.
Go read. That chunk makes my head spin a bit. It would intuitively explain a whole lot differences between the pre-eocene ecological players and the modern ones. Wow.
Consider this a call-out, Chris, to expand on that theme. Tell us more!