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Fwd: Aw: RE: Arboreal Theropods: The prize at the bottom of the cracker jack box
On Tue, Jul 23, 2013 at 6:19 PM, Jason Brougham <firstname.lastname@example.org> wrote:
> Some on this thread have mentioned that, if an animal is using trees in its
> biology, it should show specializations.
> Recent work has found an ingenious way to test the time between a behavioral
> shift and a clear morphological specialization.
> In fossil proboscideans that switched from a tree leaf diet to a grass diet
> (as marked by carbon isotope ratios) the answer is 3 million years.
> I bet that is a long interval but, then again, tooth crown height should
> increase faster (by shifting to the taller end of the pre-existing
> distribution of tooth crown heights in the population) than complete descent
> and reversal of a toe.
That's really cool! But consider that basal eumaniraptors probably had
much shorter generation times (not to mention more offspring) than
T. Michael Keesey