Re: Spinosaurine on NetLaputa website

["Jaime A. Headden" <qilongia@yahoo.com>]

Waylon Rowley (whte_rbt_obj@yahoo.com) wrote:

<There is a pretty good likeness with this cast (?) and the pic of 
_Angaturama's_ snout>

  That is not the snout of *Angaturama*, which is not complete enough to 
suggest placement of the
nares. Even the premaxillae are not complete in that taxon. The external nares 
in *Irritator* are
very strongly retracted and indicate the rostral lobe of the maxilla was close 
to 1/3 or more the
maxillary length (that's long).

  The snout shown, however, is an amalgam of the lower jaw of *Spinosaurus 
aegyptiacus* and the
upper jaw of a MNN GDF snout referred by Taquet and Russell to *Spinosaurus 
maroccanus*.
*Spinosaurus maroccanus* may, in fact, be synonymous with *S. aegyptiacus* 
(Sereno et al., 1998,
see the notes in the *Suchomimus* paper) and this may actually be plausible 
(I'm not certain I
really agree, the comparison is between a short, high cervical in the Egyptian 
one, and a longer,
lower, and more "streamlined" and less robust one in the Moroccan one (Russell, 
1992, in _Comptes
Rendus_. There may be some ontogenetic change involved, but the suggestion of 
Sereno et al. does
not have much presented data to back it up. I'd say any synonymy made in that 
manner should be
shelved until such a time an actual comparison can be made. The snout in Sereno 
et al. is not a
very likely one for another reason (aside from Taquet and Russell, 1998) in 
that the shapes of the
jaws along their dentigerous portions are completely and wholly unlike one 
another, and that the
upper jaw would pertain to a "stretch-snouted" form of perhaps 6.5-7ft long, 
and the Egyptian
skull to merely 5.5ft at the most. But that's for a subadult. The Egyptian 
specimen had only two
fully fused neurocentral sutures out of about 15 vertebrae, making it likely it 
had some good
amount of growing to do (and please do not mention recent discoveries, you all 
know what I mean).

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