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Re: Quo vadis, T. rex? [long]



At 04:40 PM 2/6/96 -0700, Jeffrey Martz wrote:
>
>>    Why?  Right now there are damn few skin impressions of theropods that can
>> conclusively show anything.  Absence of evidence is not (necessarily)
>> evidence of absence.  Given that 1) Dromaeosaurs were very closely related
>> to Archaeopteryx and 2) Archaeopteryx had feathers it makes sense that all
>> maniraptorans had feathers.
>
>     Why?  You are assuming that feathers evolved in the common ancestor 
>of all maniraptorans.  It could just have easily have been a later 
>innovation of one small group, which eventually led to Archaeopteryx.  
>Its largely a question of when feathers first appeared, something that is 
>NOT known.

   That's right.  It could just have easily been a feature of
archaeopterigians, rather than the common ancestor of maniraptorans.
However, what you said in your first post was "Assuming that any theropod
except Archaeopteryx had feathers is a much bigger assumption" implying that
that one theory carried more weight than the other.

   In any case, until _Pelicanimimus_ is fully described and put through
peer review, I think it looks more likey that at least the common ancestor
of ornithimimids and maniraptorans, rather than just the common ancestor of
maniraptorans, had feathers or were well on their way to it.

   It just crossed my mind that since pterodactyls had hairlike structures,
maybe proto-feathers are plesiomorphic for archosaurs....


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