RE: Cretaceous taeniodont

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

Thomas R. Holtz, Jr. wrote:

> One thing that seems to be driving this assumption was that mammals were in
> competition against dinosaurs BUT nothing else.  This doesn't accurately
> reflect the Mesozoic, particularly at the scale of mammals involved.  Other
> taxa need to be recognized here: sphenodontians (in the early Mesozoic),
> lizards (in the later Mesozoic), and various crocodyliforms throughout.
> Many of these may have been direct mammal competitors; others were 
> potential
> predators.

True.  I think the reason this discussion has centered on 
dinos-versus-mammals is because I have a suspicion that John Bois is using 
the apparent size increase of Cretaceous mammals as an indicator for a 
decline in dinosaur dominance.  (Am I right, John?  :-)  )  In other words, 
John is implying that mammals started getting bigger because the predatory 
pressure from non-avian theropods was slackening off for some reason in the 
Cretaceous.  I was just raising some alternative scenarios for why mammals 
might have gotten bigger.



Tim

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