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Re: Dino heart--Williston's prediction comes true!



On Mon, 1 May 2000, Stanley Friesen wrote:

> I don't have the latest cladograms, but the issue is complex.
> 
> "Proterosuchians" - the basal archosaurians - have been interpreted as 
> semi-aquatic, and as terrestrial.  Many of the earliest crocodilians per se 
> are the fully terrestrial protosuchians (note the difference in 
> spelling).  In some cladograms, at least, the protosuchians form a clade 
> that is the sister group to "modern" crocdilians.  This leaves the state in 
> the actual crocodilian ancestor uncertain, in my opinion.  Were the 
> protosuchians a terrestrial sideline, or a persistent branch of the basal 
> crocodilian group?

I have a cladogram at this URL:
<http://dinosauricon.com/taxa/archosauromorpha.html>

I think it is reasonably up to date, but, if it isn't, someone let me
know!

In this cladogram, there is no "Protosuchia", so I assume it's
paraphyletic. (Proterosuchidae, however, is a clade at the base of
Archosauriformes.) Outgroups to Crocodylomorpha (=={_Sphenosuchus_ +
_Crocodylus_}) are Poposauridae, then Postosuchidae (and
_Gracilisuchus_?), then Rauisuchidae.

-- T. Michael Keesey .................................. <tmk@dinosauricon.com>
   My Worlds (including The Dinosauricon) ... <http://dinosauricon.com/keesey>
   AOL Instant Messenger ........................................ <Ric Blayze>