Re: dino extinction

["Tim Williams" <T.Williams@cclru.randwick.unsw.edu.au>]

> >(_Tingamurra_) from the early Tertiary of Australia hints that the
> >dominance of marsupials on this continent came about not through
> >default (i.e. the absence of placentals), but because the marsupials
> >were competitively superior to placentals.

You're right.  I should have wrote "were competitively superior to
placentals IN AUSTRALIA".

>         Actually, I think it would be best to assume that other factor were
> in effect, considering other instances when placentals beat out the
> marsupials.  Perhaps marsupials just had a stronger foothold in Australia?
> As with the invasion of South America by placentals, simple "just-so
> stories" do not seem to always adequately explain evolutionary phenomena
> (although they can be useful, there is a paper in _The Beginnings of Birds_
> which covers this topic in some depth, from a more amicable perspective).





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