Gondwana Oviraptors

[Adam Yates <zooamy@zoo.latrobe.edu.au>]

On Tue, 20 May 1997, Darren Naish wrote:

> I've seen several references to a paper (by Rich and Vickers-Rich?, published
> in _Alcheringa_) on the Aussie oviraptorosaur (including both here on the list
> and in _Dinosaur Discoveries_ # 3). But will somebody please tell me what this
> paper actually says? What material is known and how does it compare to other
> theropods? Why is it assigned to Oviraptorosauria (or even to a more specific
> clade)?
> 

The paper by Currie, Vickers-Rich and Rich (1996 Alcheringa vol. 20, 
73-79) describes a possible theropod surangular and a dorsasl vertebra. 
If the bone really is a surangular (and although the bone is incomplete 
it is hard to imagine what else it could be) then it is similar in size 
and shape to that of Dromaeosaurus. However there are three oviraptorosaur 
apomorphies present. Firstly the coronoid process is medially inflected, 
the anterior and posterior surangular foramina are not present 
(presumably merged with the large external mandibular fenestra),and a 
longitudinal depression antero-lateral to the coronoid inflection 
(presumably for the insertion of the superficial pseudotemporalis). The 
lack of a concave ventral margin of the surangular and a lack of fusion 
between the surangular and the articular would suggest that the 
Australian oviraptor would be outside the Caenagnathid+Oviraptorid clade. 
The dorsal vertebra is very like a primitive maniraptoran with a single 
pleurocoel on the side of the centrum (as seen in dromaeosaurids and 
oviraptorosaurs), the authors tentatively align vertebrae with the 
surangular because the nueral spine is low and broad, like those of 
oviraptorids but unlike dromaeosaurids (sounds fairly weak to me). I'm 
only reporting my understanding of the paper here, and I don't know much 
about the distribution of the characters used, perhaps Dr. Holtz can shed 
some light on the subject.

Cheers

Adam Yates