Re: Endothermic Crocs in Nature

["T. Michael Keesey" <keesey@gmail.com>]

On 4/15/05, Tim Williams <twilliams_alpha@hotmail.com> wrote:
> 
> David Peters wrote:
> 
> >As Greg Paul has noted earlier, apparently the easiest
> >time for a taxon to revert is when it is only a few steps into the next
> >level.
> 
> Greg cites this in support of "neoflightlessness" in early birds.  This
> "rule" makes a great deal of intuitive sense; but I have yet to see any hard
> evidence (e.g., similar reversions of incipient or nascent ecomorphologies
> in other lineages).  For example, I know of no "neoflightless" insects, nor
> "neoamphibious" proto-cetaceans.

"Easier" doesn't mean "necessary". The thing to do would be to find a
clades where reversals *do* happen, and then determine if the
reversals tend to happen more often closer to the root.

--Mike Keesey