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

Psittacosaurus queries

Hey all,
For some additional non-theropod discussion...:

I'm currently trying to use the literature to discern any possible characters 
that might be able to divide _Psittacosaurus_ into two or more genera, as Jaime 
Headden and Pete Buchholz have both discussed onlist before.  I have a few 
brief questions:

First, there seems to be some confusion among different authors (okay, 
basically among the exact same author: Paul Sereno) about the presence of 
antorbital fossae in _Psittacosaurus_.  Based on all drawings and material I 
have seen there is definitely no antorbital fossa present in any known 
specimen.  Most of the literature directly says this.  However, in _Dinosaur 
Systematics_ Sereno comments that _Psittacosaurus mongoliensis_ is diagnosed by 
its small, triangular antorbital fossa.  However, in _The Dinosauria_, which 
was published in the same year, he calls the exact same structure a depression 
and writes that it "should not be confused with the antorbital fossa in other 
dinosaurs."  In the 2001 book _The Age of Dinosaurs in Russia and Mongolia_, 
Sereno seems to clarify himself by stating that _Psittacosaurus_ does not 
possess said structure, which to me seems to be correct.  But, to add some more 
confusion, in _The Horned Dinosaurs_, Peter Dodson calls the structure an !
orbital FORAMEN.  

I am fairly sure that _Psittacosaurus_ does not possess a true antorbital fossa 
(or fenestra), and that this is diagnostic of the genus.  But, am I wrong here?

Also, in his 2001 paper Sereno only recognizes six species (he discounts _P. 
sattayaraki_ and _P. mazongshanensis_ due to the paucity of both material and 
any diagnostic characters).  However, I had once read (maybe onlist) that seven 
species were recognized.  Sereno sees these as valid: _P. mongoliensis_, _P. 
sinensis_, _P. neimongoliensis_, _P. ordosensis_, _P. xinjiangensis_, and _P. 
meileyingensis_.  Am I missing any valid species?  Of coures, some of the 
others (_P. osborni_, _P. tingi_, and _P. guyangensis_ ) might be valid, but 
likely not.

Finally, I have a very difficult time accessing much of the literature, 
including, for the time being, papers in _Science_, _Nature_, and _JVP_.  If 
anyone could e-mail me scans or copies of Sereno and Chao 1988 (JVP 
14:353-365); Sereno, Chao, Cheng, and Rao 1988 (JVP 14: 366-377); Cheng, Zhao, 
and Xu 1999 (JVP 19: 681-691); and the descriptions of _P. neimongoliensis_ and 
_P. ordosensis_, I would be forever indebted! :-)  I would especially 
appreciate scans of photos or line drawings of the skulls.  And, if scans are 
impossible or difficult to send, if someone would list any diagnostic 
characters or other interesting osteological features (especially those 
regarding the premaxilla-maxilla-lacrimal-jugal joint, maxillary secondary 
depression, lacrimal foramen, and dentary) it would also be appreciated.

Any scans or files can be sent to my other e-mail address, 
brusatte@uchicago.edu, which I will start using more as I begin my 
undergraduate education at the University of Chicago in September.

Thanks, thanks, thanks!


SITE: http://www.geocities.com/stegob
ONLINE CLUB: http://clubs.yahoo.com/clubs/thedinolanddinosaurdigsite
WEBRING: http://www.geocities.com/stegob/dlwr.html
INTERNATIONAL LANGUAGE SITE: http://www.geocities.com/stegob/international.html

Supercharge your e-mail with a 25MB Inbox, POP3 Access, No Ads
and NoTaglines --> LYCOS MAIL PLUS.