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RE: Toro babies?



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=A0 The material that Hunt and Lehman use to identify the specimen as *Toro=
saurus* (and consequently also distinguish it from *Triceratops*) is the pr=
esence of a horizontal thickening of the parietal along the posterior margi=
n of the distal end=2C which is apparently lacking in *Triceratops*.

=A0 I'd note that as far as I can tell=2C virtually all ceratopsids are qui=
te close to indistinguishable until attaining what might be sexually signif=
icant or species discriminant features=2C such as horns=2C frill ornamentat=
ion=2C and nasal ornamentation. Postcranially=2C chasmosaurines differ quit=
e a lot more than centrosaurines=2C but one would have to test this with su=
bstantial samples of torosaur postcrania to match with triceratopsian postc=
rania.

=A0 Cheers=2C

=A0 Jaime A. Headden

"Innocent=2C unbiased observation is a myth." --- P.B. Medawar (1969)


"Human beings=2C who are almost unique in having the ability to learn
from the experience of others=2C are also remarkable for their apparent
disinclination to do so." --- Douglas Adams (Last Chance to See)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things=2C the human race
has had a dream: to kill him=2C so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion=
 Backs)





----------------------------------------
> Date: Thu=2C 29 Oct 2009 00:41:35 +0000
> From: df9465@yahoo.co.uk
> To: VRTPALEO@usc.edu=3B dinosaur@usc.edu
> Subject: Re: Toro babies?
>
> The only specimens in Hunt & Lehman (2008) relevant to the particular tor=
o-trike question raised here are the listed cranial elements=2C and none of=
 these are from what might be called "toro babies".
>
> All I can say is=2C wait for the paper(s)!
>
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
>
>
>
> ----- Original Message ----
> From: "Thomas R. Holtz=2C Jr."=20
> To: GSP1954@aol.com
> Cc: dinosaur@usc.edu=3B vrtpaleo@usc.edu
> Sent: Wednesday=2C 28 October=2C 2009 18:24:20
> Subject: Re: Toro babies?
>
> GSP1954@aol.com wrote:
>> Have heard a rumor that at SVP its was announced that juvenile Torosauru=
s
>> have been found showing that the genus is not an adult Triceratops=2C wo=
uld
>> much appreciate someone letting me know what's up on this (I know about
>> the
>> abstract etc favoring Toro being mature Triceratops).
>
>
> The rumor is mixed up. The specimens in question were NOT addressed at
> SVP. However=2C I brought them up on the Dinosaur Mailing List following =
a
> discussion of the Torosaurus-Triceratops situation. The paper and abstrac=
t
> in question is:
>
> Hunt=2C R..K. & T.H. Lehman. 2008. Attributes of the Ceratopsian Dinosaur
> Torosaurus=2C and New Material from the Javelina Formation (Maastrichtian=
) of
> Texas. Journal of Paleontology 82(6):1127-1138. doi: 10.1666/06-107.1
>
> Abstract
>
> A bone bed in the middle part of the Javelina Formation (Maastrichtian) i=
n
> Texas yielded parts of about 37 identifiable ceratopsid dinosaur bones=2C
> mostly appendicular and limb girdle elements belonging to one juvenile an=
d
> two adult individuals of Torosaurus cf. utahensis. The bone bed is a lag
> assemblage comprising large immobile parts of the skeletons accumulated i=
n
> an abandoned stream channel. In general form and proportions the postcran=
ial
> bones are similar to those in Pentaceratops sternbergi and are not as rob=
ust
> as those in Torosaurus latus or Triceratops horridus. A few cranial eleme=
nts
> are preserved=2C including parts of a parietal=2C squamosal=2C maxilla=2C=
 and two
> dentaries. The
> omparable to that of a more
> nearly complete specimen of Torosaurus cf. utahensis collected nearby at
> about the same stratigraphic level. The bone bed material provides a basi=
s
> for the first skeletal reconstruction of this enigmatic horned dinosaur.
> Most characters used in diagnoses of T. utahensis and T. latus are
> inadequate. Only the raised bar along the squamosal/parietal suture=2C pr=
esent
> in T. latus=3B and the midline epiparietal=2C absent in T. latus=2C may
> discriminate the two species.
>
>
> --
> Thomas R.. Holtz=2C Jr.
> Email: tholtz@umd.edu Phone: 301-405-4084
> Office: Centreville 1216
> Senior Lecturer=2C Vertebrate Paleontology
> Dept. of Geology=2C University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661
>
> Faculty Director=2C Earth=2C Life & Time Program=2C College Park Scholars
> http://www.geol.umd.edu/~jmerck/eltsite/
> Faculty Director=2C Science & Global Change Program=2C College Park Schol=
ars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
>
> Mailing Address: Thomas R. Holtz=2C Jr.
> Department of Geology
> Building 237=2C Room 1117
> University of Maryland
> College Park=2C MD 20742 USA
>
>
>
>
                                         =20
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