Re: Cretaceous taeniodont

[John Bois <jbois@umd5.umd.edu>]

On Mon, 5 Apr 2004, David Marjanovic 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?  Would one more do it?  Two?
>
> Even three thousand would not do it.

But this is a serious question.  Much is made about the explosive
diversification of mammals _after_ the K/T.  And there is good reason for
this!  But increasing evidence of diversity--especially with regard to
niche utilization and size--before the K/T is also an important
phenomenon.  My question is simply: what is the magic number of one kilo
plus mammals that will make people pay attention?

> And then there's always *Repenomamus*, bigger than any of the three and
> roughly 50 million years older, and coexisting with *Gobiconodon* which
> reached the above dimensions.

OK.  Another important phenomenon.  Why then and not later?