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Fwd: Greg Paul is right (again); or "Archie's not a birdy"
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- Subject: Fwd: Greg Paul is right (again); or "Archie's not a birdy"
- From: Jason Brougham <email@example.com>
- Date: Thu, 28 Jul 2011 12:52:34 -0400
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If the EBFF's of Beipiaosaurus, a therizinosaur, are homologous with ETFs in
Epidexipteryx then they are known outside of Avialae. Xu has hypothesized that
both functioned in display.
But I agree with you that there is not good evidence that ribbon like feathers
My point is precisely as you have suggested: Xu's new topology leaves it
unclear whether the last common ancestor between Archaeopteryx and birds was
volant or engaged in any aerodynamic behaviors at all. When you suggested that
Epidexipteryx looks secondarily flightless I wanted to point out that it could
look primitively flightless as well, given a different hypothesis.
> From: Matthew Martyniuk <email@example.com>
> Date: July 28, 2011 12:35:50 PM EDT
> To: <firstname.lastname@example.org>
> Cc: Dinosaur Mailing List <email@example.com>
> Subject: Re: Greg Paul is right (again); or "Archie's not a birdy"
> True, but on the other hand I don't think Xu has presented any
> convincing evidence that ribbon-like feathers are the primitive state.
> Prum's research suggests they are derived from normal rachides, and
> the fossil record seems to bear this out (they're nowhere to be found
> outside Avialae, at least so far). Foth 2011 agrees with this and
> interprets the ribbon-like portion of these feathers as simply a
> modified calamus. With the supposed "ribbon feathers" of juvenile
> Similicaudipteryx debunked, I don't know of any reason to consider
> them the primitive state.
> Without more specimens around the base of Paraves and especially
> Avialae, I don't think any hypothesis about their ancestral volancy
> can be supported or refuted. All we know is that we've got forms on
> both paravian branches with large wings and asymmetrical flight
> feathers. Whether or not this condition evolved convergently in
> deinonychosaurs seems to be an open question.
> On Thu, Jul 28, 2011 at 12:31 PM, Jason Brougham <firstname.lastname@example.org> wrote:
>> Certainly Epidexipteryx could be secondarily terrestrial. Then again,
>> Epidexipteryx RETAINS the ribbon like tail feathers, which Xu postulated as
>> primitive relative to flight feathers. Therefore, Epidexipteryx may be the
>> primitive one and retained primitive flightlessness, and flight may have
>> arisen in an animal closer to what Xu calls (in all three relevant studies
>> mentioned here) Epidendrosaurus and then been passed on to birds.
>> Then, in Xu's new cladogram, there is less support for the hypothesis that
>> Archaeopteryx or any deinonychosaur could fly or glide, as none of them are
>> ancestral to nor closely related to birds. There is no more support for the
>> hypothesis that any of them were flightless, either.
>> But, as Dr. Holtz and Mr. Paul have said, this new topology is not strongly
>> supported and may change again.
>>> On Jul 28, 2011, at 11:55 AM, Matthew Martyniuk wrote:
>>>> _Scansoriopteryx_, though, seems to have had relatively long wings
>>>> feathers (considering it is known only from fledgling specimens) that
>>>> form a herringbone pattern characteristic of remiges. The small arms
>>>> and lack of remiges in _Epidexipteryx_ look like a secondary loss.
>>>> Matt Martyniuk
>>>> On Thu, Jul 28, 2011 at 11:29 AM, <GSP1954@aol.com> wrote:
>>>>> There was no way that small armed Epidexipteryx flew. But its actual
>>>>> phylogenetic placement is tenuous and it may have descended from Jurassic
>>>>> I doubt we will ever be able to sort a lot of this out. In any case my
>>>>> notion was that Archaeopteryx was less derived than some "dinosaurs," and
>>>>> that some of the latter were secondarily flightless, which seems to be
>>>>> holding up pretty well.
>>>>> In a message dated 7/28/11 9:34:25 AM, email@example.com writes:
>>>>> << The new paper on Xiaotingia places scansoriopterygids as the most basal
>>>>> avialans, and Xu has opined that Epidexipteryx was flightless, raising the
>>>>> possibility (though by no means requiring) that the last common ancestor
>>>>> Archaeopteryx and crown group birds was flightless.
>>>>> That doesn't fit your theory, correct? >>
>>> Jason Brougham
>>> Senior Principal Preparator
>>> American Museum of Natural History
>>> (212) 496 3544
>> Jason Brougham
>> Senior Principal Preparator
>> American Museum of Natural History
>> (212) 496 3544
Senior Principal Preparator
American Museum of Natural History
(212) 496 3544