[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Gargantuavis a bird, not a pterosaur



For anyone who does not have the papers on Gargantuavis and Nothronychus,
I've put up the figures of the pelves here:

http://web.me.com/jasonbrougham/Site/Blog/Entries/2011/7/4_Gargantuavis_vs._Nothronychus.html



> Thank you Mickey.
>
> The ten sacral vertebrae do seem to be the character cited to diagnose
> Gargantuavis as a bird. Buffetaut and le Leouff cite Chiappe(1996), when
> they state that no non - avian dinosaur has that many sacral vertebrae.
>
> That leaves open three areas of doubt in my mind.
>
> 1) The authors were not certain of the vertebral number in Gargantuavis.
> To quote Buffetaut and le Loeuff, 1998:
>
> "...the exact number of vertebrae in the synsacrum is not easy to
> determine"
>
> and
>
> "...it appears that ten vertebrae are present...".
>
> 2) Have any non - avian maniraptorans been found since 1996 that have more
> than 8 sacral vertebrae?
>
> 3) If this type of broad, highly fused, synsacrum with neurapophyses fused
> into a low median dorsal ridge is seen in therizinosaurs such as
> Nothronychus, can we rule out the possibility that gargantuavis is a
> previously unknown species of therizinosaur?
>
> To be fair, Nothronychus' pelvis is described as dorsoventrally crushed,
> so I may be seeing more superficial similarity than there really was.
>
> -Jason
>
>
>


Jason Brougham
Senior Principal Preparator
Department of Exhibition
American Museum of Natural History
81st Street at Central Park West
212 496 3544
jaseb@amnh.org