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Re: THEROPOD CLADOGRAMS - ARGHHH!
On Mon, 5 Feb 1996, Nicholas J. Pharris wrote:
> On Mon, 5 Feb 1996 Dinogeorge@aol.com wrote:
> > Conical teeth with unserrated carinae and elliptical to circular
> > cross-section occur in _Spinosaurus_, _Siamosaurus_, _Baryonyx_,
> > _Irritator_,
> > and _Archaeornithoides_.
> > Elongate rostrum with
> > narial openings placed caudally from the tip occurs in _Baryonyx_ and
> > _Irritator_, material unavailable for _Spinosaurus_ and (I think)
> > _Archaeornithoides_.
> Of course, both of these characters may well be directly related to
> piscivory. They are also found in many pterosaurs.
And birds(i.e. Hesperornis, and especially herons)
> I don't know if I would advise making sweeping statements about theropod
> phylogeny based on tooth characters.
Ok, so there are alot of character missing to really support a
connection. I think that we connot rule out a possible connection until we
find some post-cranial material from _Irritator_ AWA more _Spino_ material.
> > > Sagittal cranial crest occurs in _Irritator_ and
> > _Baryonyx_, material unavailable for _Spinosaurus_ and _Archaeornithoides_.
> Troodontids have fairly descent sagittal crests, too.
When we have only one specimine how can we not rule out sexual
dimorphism for anything including the sagittal crest.
> > Considering the incredible scarcity of material for any of these taxa, this
> > character suite isn't too bad. What's Martill talking about? I wouldn't
> > place
> > any of these genera together in the same family (there are four families
> > here
> > plus Spinosauria _incertae sedis_), of course, but they could well have
> > shared a common ancestry somewhere in the Late Jurassic Coeluria.
> If they are related at all, they are, IMHO, most likely related to
> troodonts, based on similarities between that family and _Irritator_ and
> _Archaeornithoides_. Just like everyone else, I am eagerly awaiting any
> concrete info. on Russell's _Spinosaurus_ material.
I think somebody needs to find an _Irritator_ in Africa. (It would be a
great place to look)
> Nick Pharris
Preparator,Dept. of Earth Sciences
Pacific Lutheran University
Tacoma, Wa, 98447
"Very funny Scotty, Now beam down my clothes."