Re: Szechuanosaurus

[pharrinj@PLU.edu]

On Sat, 6 Jan 1996 Dinogeorge@aol.com wrote:

> In a message dated 96-01-06 01:24:00 EST, you write:
> 
> >According to Paul, the original specimen described as _S. campi_ was an 
> >isolated tooth.  A sinraptorid skeleton was later referred to _S. campi_ 
> >because several teeth similar to the type were found nearby.  However, 
> >again according to Paul, these are likely not to be the teeth belonging 
> >to the skeleton but rather those of a theropod scavenging on the 
> >carcass.  C.C. Young described _S. campi_ in 1942, in 
> >
> >"Fossil Vertebrates from Kuangyuan, N. Szechuan, China", Bull. Geol. Soc. 
> >China 28:187-209 (the ref is from _Dinosauria_; I don't know what Bull. 
> >Geol. Soc. refers to; I hope you do). 
> >
> >But I don't know whether that description is of the original tooth or of 
> >the skeleton.
> 
> The type series (from Young, 1942) is several teeth, from which one may later
> have been selected as the lectotype by someone else. I have photos of the
> skeleton, which I think has a fake, or at least very incomplete, skull and
> other problems. It hasn't been described yet, probably because everyone in
> China seems to accept its identification as _Szechuanosaurus campi_ and they
> don't realize that it contains much new material that should be published on.
> 
> As to its being a sinraptorid, that's indeed possible, but I would need to
> see some clearer photos of the skeleton to confirm this. Dong (1992),
> however, notes "coossified ischium and pubis," and the pubis has only a small
> pubic "foot," suggesting ceratosaurian affinities.
> 

Features shared by _Sinraptor_ and _Yangchuanosaurus_ include a low, 
caudally-directed flange on the caudal margin of the ischium and a slight 
rostrally directed hooking of the end of the ischium.  The 
"_Szechuanosaurus campi_" ischium shows both of these features.

The pelvis is figured in _the Dinosauria_, on page 183.  The figure is 
taken from:

Dong Z., Zhou S., and Zhang Y., 1983.  [The Dinosaurian Remains from 
Sichuan Basin, China].  Palaeontologica Sinica 162:  1-145.

(in Chinese with an English summary).

The pubic foot in this species is shorter than that in _Yangchuanosaurus_ 
but longer than that shown for _Sinraptor_ in the Fall, 1994, issue of the 
_Dinosaur Report_, from the Dinosaur Society, on page 16.  It is similar 
to the pubic expansions in those species in that the distal pubis is 
expanded only caudally.

I've never heard of a ceratosaur with ANY pubic foot to speak of.

The dorsal vertebral neural spines, while shorter than those of _Y. 
shangyouensis_ (_PDW_, p. 290), are bladelike (_Dinosauria_, fig. 6.5E, 
p. 179, after Dong et al., 1983--see above).

Looks sinraptorid to me.

     Talk to you later,

     Nick Pharris
     Pacific Lutheran University
     Tacoma, WA