Re: Cretaceous taeniodont

["David Marjanovic" <david.marjanovic@gmx.at>]

> But the shift from shrew-sized mammals to
> wolverine-sized mammals in Cretaceous mammal dimensions (in North America,
> anyway) may have been due to some anatomical innovation(s) in the
placental
> lineage.

Not in the placental lineage -- *Didelphodon* is a close relative of the
marsupials. And *Gobiconodon* and *Repenomamus*, of course, are something
else entirely...

> But I don't think we should assume that it was always
> external factors that were keeping mammals small (e.g., quality of the
> predators) in the Mesozoic.

Good point.