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re: other thoughts on Prolacertiforms -



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/