RE: New papers on the dinosaur formerly known as Syntarsus (no more "Megapnosaurus")

[Brad McFeeters <archosauromorph2@hotmail.com>]

> From: Tim Williams <twilliams_alpha@hotmail.com>
> Reply-To: twilliams_alpha@hotmail.com
> To: dinosaur@usc.edu
> Subject: RE: New papers on the dinosaur formerly known as Syntarsus (no 
> more "Megapnosaurus")
> Date: Tue, 28 Jun 2005 17:57:14 -0500
>
> The nomenclatural issue is separate from the phylogenetic/taxonomic issue.  
> _Megapnosaurus_ is a valid name, since Ivie et al. (2001) followed ICZN 
> guidelines for providing a replacement name for _Syntarsus_ Raath, 1969 
> (non _Syntarsus_ Fairmaire 1869).  The fact that Raath was not given the 
> opportunity to do this himself is unfortunate, but does not subtract from 
> the validity of _Megapnosaurus_.  (Unless the ICZN deems it to be so in 
> response to an official petition.)  I hate the name _Megapnosaurus_,  and I 
> regret the way it was named - and I'm glad it's sunk into _Coelophysis_.  
> But this is another issue, tied up with phylogeny and taxonomy: as a 
> subjective junior synonym of _Coelophysis_, the *genus* _Megapnosaurus_ is 
> invalid.  But the *name* itself valid, and it will stand as the available 
> name for _S. rhodesiensis_ unless overturned by fiat by the ICZN.

Bristowe & Raath only discuss the taxonomic issue, not the nomenclatural 
issue.  Yes, we might see "Megapnosaurus" revived some day.  The taxomonic 
analysis in Bristowe & Raath discusses only cranial characters, so a 
comparison of the postcrania could give us a different conclusion.

Has anyone else noticed that Tykoski & Rowe's chapter on Ceratosauria in 
_The Dinosauria 2nd Edition_ has this entry in the taxon list (p. 48)?

---

Syntarsus Raath, 1969) (=Megapnosaurus
Ivie, Slipinsky, et Wegrzynowicz, 2001)

S. rhodesiensis Raath, 1969
(=Megapnosaurus rhodesiensis [Raath,
1969])

S. kayentakatae Rowe, 1989
(=Megapnosaurus kayentakatae [Rowe,
1989])

---

Something doesn't make sense here.

> I believe Alex Downs found the exact same thing, a few years back.  He also 
> regarded _S. rhodesiensis_ as a species of _Coelophysis_.

I've read his paper.  I'll read it again when I get back home.

> I was going to ask the same question.  After all, _kayentakatae_ does have 
> nasolacrimal crests.  OK, these crests are much lower than those of 
> _Dilophosaurus_, but they are there nonetheless.

Unless you think the crests imply *Dilophosaurus* and *C. kayentakatae* are 
sister taxa, this seems irrelevant to me.   After all, *C.*/"S." 
*kayentakatae* has been considered congeneric with crestless coelophysoids 
since the day it was named....

The new *C. rhodesiensis* specimen QG165 is described as having a "crest" 
much lower again than in *C. kayentakatae* (3 mm).  However, this "crest" 
may exist only on the right side of the skull, and the authors consider it 
more probable to be an artefact of distortion.  :\