Re: Placement of Segnosauria (was Re: Details on Nanshiungosaurus bohlini)

["Timothy Williams" <twilliams_alpha@hotmail.com>]

T. Mike Keesey wrote:

> I mention "indeterminate material (neck vertebra) -- late Late Jurassic --
> U.S.A.". Looking back in the DML archives, I find this quote from Timothy
> Williams: "There's also possible oviraptorosaur[s] from the mid-Cretaceous
> of Australia and Brazil, and a caudal vertebra from the Morrison." I must
> have made an error when I wrote "neck vertebra" -- will correct shortly.


Here's the info on the oviraptorosaur/segnosaur vertebrae from Wyoming and 
South America (and apologies to Mike and everyone else if this contradicts 
an earlier post of mine).

YPM 1996 and 1997: Two cervical vertebrae, probably fifth and fourth 
respectively, previously referred to _Coelurus fragilis_.
Locality: Quarry 9, Como Bluff, Wyoming.
Horizon: Morrison Formation.

Mackovicky (1997) held off naming this small theropod, even though the 
cervicals shows unique features which distinguish YPM 1996/1997 from other 
small theropods.  The cladogram of Frankfurt and Chiappe (1999), based on 
cervical morphology, placed YPM 1996/1997 on the 
therizinosaur/oviraptorosaur lineage, and basal to both Therizinosauridae 
and Oviraptoridae.  This paper also described a possible oviraptorosaur from 
the Late Cretaceous of Argentina, based upon a single cervical vertebra:

MACN-622: Cervical vertebra (fourth or fifth).
Locality: Estancia El Brete, southern Salta Province, Argentina.
Horizon: Lecho Formation.

There's also putative oviraptorosaur material dotted around Gondwana, 
including a partial sacrum from the Santana Formation described by Frey and 
Martill (1995), and stuff from Dinosaur Cove (partial jaw, vertebra)in 
southeastern Australia.

References

Frankfurt, N.G. and Chiappe, L.M. (1999).  A possible oviraptorosaur from 
the Late Cretaceous of northwestern Argentina.  J. Vert. Paleont. 19: 
1010-105.

Mackovicky, P.J. (1997).  A new small theropod from the Morrison Formation 
of Como Bluff, Wyoming.  J. Vert. Paleont. 17: 755-757.

And Tracy Ford wrote (in reply to my earlier post)...

> (a) and (b) refer to the association of the _Beipiaosaurus_ type material.
> There's nothing that suggests to me that the material is chimeric.
>
> I disagree. The jaw is way to small to fit an animal with the body size 
> that
> the skeleton suggests. The manus and claws is too dromaeosaurid for me.
> Tracy

Even allowing for the fact that segnosaurs/therizinosaurs have very small 
heads?  You could be right though.


Tim
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at 
http://profiles.msn.com.