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Re: THEROPOD CLADOGRAMS - ARGHHH!



In a message dated 96-02-05 11:49:33 EST, dwn194@soton.ac.uk (D.W.Naish)
writes:

>I'm currently slogging through several 100 messages: it ain't *all* fun.
Soon
>as I do, I'd like to get a bit of a debate going on spinosaurs: David
Martill
>has just told me (1) _Irritator_ demonstrably lacks spinosaurid characters,
>(2)
>material recently referred to _Spinosaurus_ is _incertae sedis_ and doesn't
>match up with the type stuff, and (3) any postulated link between _Baryonx_
>and
>_Spinosaurus_ is imaginary! 
>
>

Boy, that Taquet certainly started something when he referred those
baryonychid premaxillae from Morocco (or wherever) to _Spinosaurus_ sp.,
didn't he?

Conical teeth with unserrated carinae and elliptical to circular
cross-section occur in _Spinosaurus_, _Siamosaurus_, _Baryonyx_, _Irritator_,
and _Archaeornithoides_. Vertically expanded dentary symphysis occurs in
_Spinosaurus_, _Baryonyx_, 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_. Sagittal cranial crest occurs in _Irritator_ and
_Baryonyx_, material unavailable for _Spinosaurus_ and _Archaeornithoides_.

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.