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RE: Fw: Spinosaurus questions
Jean-Michel Benoit wrote:
In a _quite_ recent post it was mentioned that *Spinosaurus aegyptiacus*
could be a chimera. Given that lost photographs of the type specimen have
recently been recovered, and that Stromer cannot be suspected of having
faked its discovery, on what basis is this assumption
I'm pretty sure (i.e. certain) that nobody is accusing Stromer of fakery.
However, it is theoretically possible that the material referred by Stromer
to _Spinosaurus aegyptiacus_ belong to more than one taxon (given that the
skeleton was incomplete and not articulated). If true, it would be an
honest mistake on Stromer's part (and Markgraf's too, who actually collected
the material, and who noted the close association between the various
elements). Smith et al. (2006) note that Rauhut (2003) brought up this
possibility of a chimeric _Spinosaurus_ type specimen, but they do not
discuss this issue further, which was outside the scope of their paper.
It's been suggested that the cervical, dorsal, and caudal vertebrae each
come from a different taxon. In brief, it was proposed that the morphology
of the tall-spined dorsal vertebrae is too different from the morphology of
the short-spined cervicals to belong to the same animal; and, although the
skull (or the parts that are known) of _Spinosaurus_ closely resembles that
of _Baryonyx_/_Suchomimus_, the structure of the dorsal centra are
reportedly quite different between _Baryonyx_/_Suchomimus_ and _Spinosaurus_
(though the _Spinosaurus_ type dorsals are clearly tetanuran). Lastly, the
proximal caudal is allegedly too large to belong to the _Spinosaurus_ type,
and might be ornithischian.
I'm not actually advocating the above interpretation; I'm just reiterating
what's been written elsewhere. I don't know enough to weigh in on the
argument, and I'll keep all of Stromer's _S. aegyptiacus_ type material in
the same taxon until there's a compelling reason not to do so.
Hope that helps.