Re: Ah ha! That's where therizinosaurs came from

[Mike Keesey <keesey@gmail.com>]

On Mon, Aug 15, 2011 at 11:01 AM,  <GSP1954@aol.com> wrote:
>>
>> In a message dated 8/15/11 10:44:05 AM, keesey@gmail.com writes:
>>
>>  On Sun, Aug 14, 2011 at 9:42 PM, Tim Williams <tijawi@gmail.com> wrote:
>>
>>> The biggest problem with GSP's "neoflightless" hypothesis is this:  It
>>> proposes that tree-dwelling theropods had plenty of time to evolve an
>>> extensive list of "flight-related" characters (advanced
>>> scapula-coracoid morphology; foldable forelimbs; shorter and distally
>>> stiffened tails; large contour feathers on the limbs and tail; etc).
>>> But over this same time, these tree-dwelling theropods didn't get
>>> around to evolving any arboreal characters.  I find this perplexing.
>>
>> That's only a problem if you assume that "trees-down" is an essential
>> part of the neoflightless hypothesis. It doesn't seem to me that it
>> is. The neoflightless hypothesis may still be valid if avialans
>> (apomorphy-based sense) developed flight from the ground up.
>
> Correct. The strict neoflightless hypothesis does not require arboreality.
> I think it did but that's another matter.

Curious to see your response to Tim's criticism, then.

I haven't seen any response to something Mike Habib posted earlier, too:

Michael Habib wrote:
> One of the reasons the dichotomy was thought to exist (and still does today)
> was a mistaken assumption that arboreal and terrestrial launch in birds are
> fundamentally different, which they are not. In fact, they are almost 
> identical.

If launching from trees and from the ground are "almost identical",
why would we need to invoke arboreality in animals that don't have any
signs of being arboreal?

-- 
T. Michael Keesey
http://tmkeesey.net/