RE: II CLPV talk summaries: Day 2

[Tim Williams <twilliams_alpha@hotmail.com>]

Scott Hartman wrote:

> Diego Pol presented data from new specimens of Mussaurus.  [snip]  Good 
> thing too, as his phylogenetic analysis found that Mussaurus is quite a bit 
> closer to true sauropods than Plateosaurus is.

It'll be interesting to see how this ties in with Yates (2004), who alluded 
to the non-prosauropod nature of _Mussaurus_ based on a number of 
characters, including procumbent teeth in the upper and lower jaws.

Yates, A.M. (2004). _Anchisaurus polyzelus_ (Hitchcock): The smallest known 
sauropod dinosaur and the evolution of gigantism among sauropodomorph 
dinosaurs.  Postilla 230: 58 pp.

> Sterling Nesbitt gave one of my favorite talks of the conference.  He 
> showed that Shuvosaurus is not an ornithomimid (no real surprise there), 
> but is rather a derived suchian.

This directly contradicts previous work that puts _Shuvosaurus_ in the 
Theropoda, based on a long list of theropod characters in the skull.  If 
_Shuvosaurus_ is a crurotarsan, then homoplasy is rampant indeed.

> Randall Irmis was up next, and picked up where Sterling left off; they feel 
> that a lot of North American Triassic dinosaurs aren?t and made a pretty 
> convincing argument for it.  A (non-
> comprehensive) list includes Eucoelophysis, which they feel pretty strongly 
> is a silesaurid.  Which makes the name EU-coelophysis ironic, to say the 
> least.

Yes - especially considering that Sullivan and Lucas (1999) believe that the 
original type specimen of _Coelophysis bauri_ (AMNH 2722) is probably 
referrable to _Eucoelophyis baldwini_.  I wonder if it is possible that the 
hypodigm for _Eucoelophysis_ might be chimeric, and include both theropod 
and non-dinosaurian material.  If not, and if the original _C. bauri_ 
holotype is in fact non-dinosaurian, *and* the holotype of _E. bladwini_ 
belongs to the same non-dinosaurian taxon, then the name _Eucoelophysis_ may 
indeed be appropriate.  However, AMNH 2722 does look rather theropodan.

> Gojirosaurus they feel is a chimera (Ken, want to comment?), made up of 
> theropod material and Shuvosaurus (or shuvosaur-like suchian) material.

The idea that _Gojirasaurus_ and _Shuvosaurus_ are the same animal has been 
floating around for a while now.  This means that the teeth that were found 
with the type _Gojirasaurus_ material belong elsewhere, since _Shuvosaurus_ 
is toothless.

Speaking of chimeras... like Mickey, I'm curious what happened to 
_Alwalkeria_.

Thanks for the postings, Scott.  They were extremely helpful and 
interesting.

Cheers

Tim