Re: Cretaceous taeniodont

["Tim Williams" <twilliams_alpha@hotmail.com>]

John Bois wrote:

> How  many species need to be
> above, say, one kg. before we can say predation and/or competition was no
> longer keeping mammals small?

Hmmm... maybe the size increase has little to do with the predators 
themselves (presumably theropods), but something that the mammals started to 
do differently.  Perhaps mammals got smarter, or faster, which allowed them 
to better evade capture.

There is a tendency, I think, to view Mesozoic mammal evolution exclusively 
through the prism of dinosaurian dominance.  Of course, it was undoubtedly 
the dominance of dinosaurs that kept mammals to growing up to sheep- or 
elephant-sized in the Mesozoic, as they did in the following Cenozoic (after 
the big dinos went bye-bye).  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.  Better sensory capabilities, keenr intelligence, better locomotory 
abilities... I dunno.  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.



Tim






Would one more do it?  Two?
> Also, if any of these mammals were burrowers what are the chances we would
> find their burrowers?
> Thanks.

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