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Re: Leviathans



John V Jackson wrote:
> 
> In reading Chris B's Deinosuchus paper in Nature, I noticed what a fantastic
> specimen that _D_ skull is! 

Uh... to quote the great Wann Langston, that skull is a "figment of the
imagination."  The picture we published was intended to show size, NOT
morphology.  Larger versions of that photo show what's real (very
little) and what's reconstructed (most of it), as the plaster was a
slightly different color from the actual bone.  It was reconstructed on
the basis of a large saltwater croc, and based on what several groups
have independently found in the past few years, the actual skull would
have looked very different.  

Wann collected a nearly complete jaw back in the 1960's - that's what
Greg and I used as the basis for our size reconstructions - and by
itself, it indicated a more gracile skull.  Since then, he/we collected
more complete cranial material in West Texas, and David Schwimmer has
some nice material from Georgia.  There's also a lot of material from
New Jersey, but it's not as complete.  So we might know more in a few
years.  In the meantime, I have a little to say about it in the
forthcoming alligatoroid phylogeny, but unless you're a hardcore clade
runner, you won't care much.



> 
> (Also looked for Chris himself standing behind the skull - couldn't see a
> stocky, pleasant-looking chap with straight, light brown, slightly thinning
> hair.  Actually he wasn't in the picture at all, so we may never know what
> he looks like!)


Since the picture was taken in the 1940's, there's little likelihood I'd
have been there, my having been born a few decades later.  The bald guy
in it is Barnum Brown.

Not sure I would describe myself as stocky or with thinning hair, but
perhaps others would.


> 
> If that characteristic kinked snout (we're back to _D_ again now) was a
> piscivorous feature - they must have been very big pisces for it to be
> retained in _D_!


Not sure what you mean by "kinked snout."  If you mean the notch between
the maxilla and premax for the dentary fang(s), that's a plesiomorphic
trait lost in a subset of alligatoroids.  If you mean the upturned
naris, that's something we see in several croc groups independently, but
which was reconstructed on the Deinosuchus skull you saw.  I don't
recall if the real thing had it or not - I'll have to check my notes. 
But it did really have the notch.  It's an alligatoroid, but a VERY
basal one.


chris


-- 
----------------------
Christopher A. Brochu
Department of Geology
Field Museum of Natural History
Roosevelt Road at Lake Shore Drive
Chicago, IL 60605

voice:  312-922-9410 x469
fax:  312-922-9566
electronic:  cbrochu@fmppr.fmnh.org