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Re: phytosaurs/parasuchians/PJ Crush
----- Original Message -----
From: "David Peters" <firstname.lastname@example.org>
Sent: Sunday, November 28, 2004 4:36 AM
Walker suggested that phytosaurs and proterochampsids were sister taxa.
A short cladistic analysis indicates it might be true. Any stoppers?
(.that is, any reason not to associate the two clades?)
Considering... I think... all phylogenetic work on basal archosaur(iform)s
that has been done in my lifetime, I think you should pose the question the
other way around: What do those two clades share, except a general croc
shape and lifestyle?
But to answer your question, off the top of my head... phytosaurs are
clearly inside the crown-group Archosauria, lacking palatal teeth, and
inside Crurotarsi, having a "crocodile-normal" (CN) ankle. Proterochampsids
are clearly outside both, retaining a row of teeth on each pterygoid and a
"modified primitive mesotarsal" (MPM) ankle. (That they lack other palatal
teeth, however, is considered a character state that puts them close to the
Sometime (next weekend?) I'll dig up the paper that describes *Yonghesuchus*
and finds it as the sistergroup of the crown-group Archosauria. It has a
cladistic analysis with more than the two characters I've explained here.