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Re: Samson the T. Rex



Agreed, just because one 'large' T. rex has proven to have medullary bone, it 
doesn't mean that ALL 'large' T. rex specimens are therefore female. There has 
to be a lot more sampling before such a supposition can be made, and just like 
line of arrested growth age analyses, this type of sampling is hampered by the 
fact that there aren't a ton of nice, undistorted, taxonomically sound T. rex 
long bones out there.

The concept of a 'robust' and 'gracile' morph of T. rex existing A) ignores the 
fact that juvenile members of the species are much more gracile than the adults 
and B) most of the characteristics that distinguish these morphs are cranial 
ones. It's been shown that tyrannosaurids have a significant degree of 
individual variation in their crania, much like we do, especially given the 
effects of aging. Many T. rex crania have the added bonus of pathologic 
injuries, distorting the characteristics used to determine the morphs. 

In the end, like Scott says, the sample size is too small (for now anyway!) to 
make any conclusions about sexual dimorphism in T. rex specifically, especially 
when those conclusions include subjective characters.

Michelle Pinsdorf
South Dakota School of Mines and Technology

--- On Fri, 10/2/09, dinoboygraphics@aol.com <dinoboygraphics@aol.com> wrote:

> From: dinoboygraphics@aol.com <dinoboygraphics@aol.com>
> Subject: Re: Samson the T. Rex
> To: tehdinomahn@live.com, 
> Date: Friday, October 2, 2009, 1:52 PM
> Despite what you may have read, there
> is no real evidence for discrete 
> morphs.  The idea of "robust" and "gracile" requires
> an actual 
> population of adults that lived at the same time and place
> (like the 
> Ghost Ranch Coelophysis quarry); T. rex specimens are from
> different 
> times and places and are not known in large enough numbers
> for anyone 
> to establish the existence of two separate morphs. 
> Even come the day 
> when we (hopefully) have enough adults to test this, it
> will be hard to 
> separate sexual dimorphism from ontogenetic variation and
> potential 
> evolutionary changes across geologic time (especially since
> many older 
> T. rex finds do not have perfect stratigraphic data
> recorded).
> 
> Statements that imply two separate adult morphs are
> quantitative claims 
> and cannot be supported just because so-and-so says that
> specimen A 
> looks robust to them while specimen B looks gracile. 
> The only T. rex 
> we can confidently sex so far is the one Mary Schweitzer
> described with 
> sex-linked tissues in the meduliary cavity.
> 
> 
> Scott Hartman
> Science Director
> Wyoming Dinosaur Center
> 110 Carter Ranch Rd.
> Thermopolis, WY 82443
> (800) 455-3466 ext. 230
> Cell: (307) 921-8333
> 
> www.skeletaldrawing.com
> 
> 
> -----Original Message-----
> From: Michael Erickson <tehdinomahn@live.com>
> To: deathspresso@yahoo.com;
> dinosaur@usc.edu;
> 
> soylentgreenistrex@yahoo.com;
> csaconn@triad.rr.com
> Sent: Fri, Oct 2, 2009 12:11 pm
> Subject: RE: Samson the T. Rex
> 
> 
> 
>  <140597.91295.qm@web54103.mail.re2.yahoo.com>
> Content-Type: text/plain; charset="Windows-1252"
> Content-Transfer-Encoding: quoted-printable
> MIME-Version: 1.0
> 
> 
> Yes=2C there is evidence (read: proof) that the "robust
> morph" 
> *Tyrannosaur=
> us rex* are female. It seems that MOR 1125 (or "B. rex")=2C
> the 
> specimen Ma=
> ry Schweitzer extracted medallary tissue from back in
> 2005=2C is a 
> robust m=
> orph. Medallary tissue=2C of course=2C occurs oinly in
> gravid or 
> nesting fe=
> male birds. So there you go=2C the "large Tyrannosaurs" are
> female.
> =20
> ~ Michael=20
> 
> ----------------------------------------
> > Date: Fri=2C 2 Oct 2009 10:19:05 -0700
> > From: deathspresso@yahoo.com
> > To: dinosaur@usc.edu=3B
> soylentgreenistrex@yahoo.com=3B
> 
> csaconn@triad.rr.=
> com
> > Subject: Re: Samson the T. Rex
> >
> > Why do "we" think that large Tyrannosaurs are female?
> Is there any 
> real e=
> vidence? Good piece of logical thinking that points us that
> way? If 
> so=2C p=
> lease point me toward.
> >
> > If I were super rich=2C buying this T-Rex=2C male or
> female=2C would 
> be o=
> ne of my indulgences. Just don't tell my girlfriend Megan
> Fox.
> >
> > Andrew Simpson
> >
> > --- On Fri=2C 10/2/09=2C csaconn@triad.rr.com
> wrote:
> >
> >> From: csaconn@triad.rr.com=20
> >> Subject: Re: Samson the T. Rex
> >> To: dinosaur@usc.edu=2C
> soylentgreenistrex@yahoo.com
> >> Date: Friday=2C October 2=2C 2009=2C 4:18 AM
> >> Hello=2C
> >>
> >> Samson is being auctioned off tomorrow in Las
> Vegas. I've
> >> been trying to win the Powerball Lottery so I
> could bid but
> >> that hasn't happened :) Anyway=2C here's a link to
> the
> >> auction. The auction catalogue is definitely
> worth
> >> purchasing for the 15 pages or so of color photos
> and
> >> commentary by Peter Larson.
> >>
> >> 
> http://www.bonhams.com/cgi-bin/public.sh/pubweb/publicSite.r?sContinent=
> =3DUSA&screen=3DlotdetailsNoFlash&iSaleItemNo=3D4372303&iSaleNo=3D17517&i
> Sa=
> leSectionNo=3D1
> >>
> >>
> >>
> >> ---- B tH=20
> >> wrote:
> >>> Wow=2C I just realized I had an 8-page
> article
> >>> in the May 2006 issue of DISCOVER ("How To
> Build a T.
> >> Rex") on this guy.
> >>>
> >>> Lots of nice pics with the article.
> >>>
> >>> He was really fragmented!
> >>>
> >>> Anybody here ever seen the mounted skeleton?
> >>> Impressions?
> >>>
> >>>
> >>>
> >>>
> >>
> >
> >
> >               
>      =0A=
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