Re: remains of spinosauridae

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

Jaime Headden wrote-

>   Once again, referral mus be affirmed by holotypes, not by referred
> material except were referred material cannot be in anyway differed from
> their types. An example from the above snipped comments. Mickey shows how
> the type cervical of *S. maroccanus* compares between *Baryonyx* and *S.
> aegyptiacus*, and asserts that referred dentition (which is applied by
> geography, not morphology or more complete material, which is lacking)
> indicates they are "nearly identical."

Are other people understanding me?  Was I so unclear?
No Jaime, I did no such thing.  I said that because S. marocannus vertebrae
fall within the expected range of positional variation for S. aegyptiacus
(based on variation seen in Baryonyx), the two Spinosaurus species are
synonymous.  The comment about their known crania being "essentially
indistinguishable" was merely to show none of the originally referred
remains differ from S. aegyptiacus much.

> Rather, the condition of the
> vertebrae would appear to show that *S. maroccanus* has baryonychine
> vertebrae, or is intermediate between a baryonychine and spinosaurine
> morphology; the dentition is questionably associated, as neither the type
> cervical nor any cervical material is unquestionably associated with
> cranial material; the association of most of the referral is based on the
> material being Moroccan in geography, and not Egyptian. Furthermore, as
> stated by Stromer at least, the cervical vertebrae lack complete neural
> spines, and are broken distally, showing there is no definitive length.
> *Acrocanthosaurus*, though not a spinosaurid, shows that much longer
> cervical spine lengths _are_ possible for another theropod, and this is an
> unknown quantity to compare *S. marocanus* to. Thus, the Moroccan taxon
> can only be reasonably compared in this sense to the English taxon; the
> Eqyptian form is indistinct, and has different proportions relative to the
> centrum and neural spine to the Moroccan, which Mickey was well to
> indicate a likely similarity to the English form. Would one not then
> conclude that *S. maroccanus* should be referred to *Baryonyx*, rather
> than refer *S. maroccanus* to *S. aegyptiacus* on the basis of referred,
> non-associated cranial material to imfer the presence of a possibly
> congeneric or conspecific form to the Egyptian taxon? Does the jaw not
> belong to the same taxon as the rostrum described in 1996 by Taquet and
> Russell, SAM 124? What other criteria would indicate the spinosaurine
> material from Morocco belong to the same taxon as the Egyptian skeleton?

Nothing suggests that S. marocannus has baryonychine vertebrae.  You
misunderstand again.  The holotype and referred cervicals of S. marocannus
are supposed to differ from S. aegyptiacus in a few ways.  I showed that
cervicals of Baryonyx differ from each other in equivalent and comparable
ways.  The referral of the cranial material is unimportant except to show no
cranial evidence for multiple Spinosaurus species exists within the material
described by Russell (1996).  Vertebra b of Stromer (1915) does include a
nearly complete neural spine, missing only the anterior edge.  "In "b" in
contrast the processus spinosus rises up rather vertically in general on the
posterior half of the neural arch roof and was clearly about 18 cm high and
8 cm broad and truncated dorsally.  Its damaged anterior edge apparently
stood up from the anterior end of the roof dorsally somewhat posteriorly,
then first as the posterior edge vertically.  This is simple, blunt, and
about 8 cm over the posterior articular surface."  The only reason I even
mentioned neural spine length was because you said "the centrum proportions
versus the shorter neural spine to size distinguishes the two species".  And
the proportions of S. marocannus are NOT suggestive of similarity to
Baryonyx, the latter of which also has vertebrae of S. aegyptiacus
proportions.  Rather, the point was that the Spinosaurus species' cervicals
vary from each other in the same way as do different vertebrae in the same
neck of Baryonyx, suggesting the differences are due to positional
variation.  The Spinosaurus material described later by Taquet and Russell
may be referrable to S. aegyptiacus too, but is inconsequential to this
debate.

The rest of your post (though containing a few useful points) was mostly a
response to you thinking I claimed synonymy based on the referred dentaries.

Mickey Mortimer