re: other thoughts on Prolacertiforms -

["silvio.renesto" <silvio.renesto@uninsubria.it>]

David Peters wrote:
> First of all, Silvio's thoughts are right on the mark, and he supports his 
> arguments with evidence you can visit on the web or in Switzerland.

For instance you may go to 
http://users.unimi.it/vertpal/galleriafossili/best-rettili/tanystropheus.htm 
my former website.  Something hopefully will appear soon also in my new 
website.  I'll inform those interested.


> T. Michael Kessey wrote:
>
> I think there's a consensus that they are basal archosauromorphs. The dissent
> lies in:
>
> - whether they form a natural group (synonymous with _Prolacertiformes_), or
> are just a polyphyletic assemblage of non-archosauriform archosauromorphs
>
>
> >>>>New work, soon to be published, will show the former is correct. At 
> least among the non-scrappy taxa.

 Well,   Rieppel, Fraser & Nosotti have just published (December 
2003),  in a rather obscure italian journal, quoted in the paper on Science 
a review of prolacertiform, sorry, protorosaur phylogeny. after putting 239 
characters (taken mainly from the works by Benton & Allen  1997, Jalil 1997 
and Dilkes 1998) in the matrix, they concluded that
1) Protorosauria  should be paraphyletic with Prolacerta more closely 
related to Proterosuchus + Euparkeria than to Macrocnemus and its allies 
(tanystropheids etc.),  Protorosaurus position changes slightly according 
to what taxa are included/excluded in the analysis. This does not occur for 
Prolacerta which stays firmly as a sister group of Proterosuchus+Euparkeria.
2) Macrocnemus, Tanystropheus and Langobardisaurus form a monophyletic 
group (not really a great surprise).
 3) Rhynchosaurus and Trilophosaurus are sister taxa of the whole 
paraphyletic "protorosauria"  bunch.

These  conclusions are quite similar to those of Dilkes 1998.

Cheers,

                                              Silvio Renesto




_

" Men take in great consideration what falls within their sphere of 
knowledge, but they don't realize how much it depends from what is beyond 
that""
                                                        (Zhuang Zhi)


Prof. Silvio Renesto
Department of Structural and Functional Biology
Università degli Studi dell Insubria
via Dunant 3
21100 Varese
Italy
phone +39-0332-421560
e-mail: silvio.renesto@uninsubria.it
see my Triassic website at http://dipbsf.uninsubria.it/paleo/