[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Even more concerning the Triceratops/Torosaurus deal

Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

=A0 I appreciate the idea that we should all wait for the papers before com=
menting on this=2C as the waiting for the official material and statements =
of association providing this hypothesis give more to discuss=2C as well as=
 providing the meat of the data with which to do so.

=A0 But...

=A0 The authors have not only entertained discussion=2C they did so with a =
press release validating the release of their abstracts from SVP/SVPCA. It =
seems untenable to argue that after they promoted discussion that we should=
 simply lay silent.

=A0 As an example of why more demonstration or discussion would be helpful=
=2C the same was done with development of pachycephalosaur "implosion" (red=
ucing four Maastrichtian pachys to two being a "significant" alteration of =
the proposed taxonomy) by some of the same authors. This resulted in an ope=
nly-discussable paper that has as part of its conclusion the rather firm si=
nking of *Dracorex* into *Pachycephalosaurus* by way of *Stygimoloch*. A su=
bstantial amount of the paper is taken to demonstrate metaplastic transform=
ation and development of the horns and domes in *Dracorex* and *Stygimoloch=
*=2C and from this the authors conclude that they are synonyms (apart from =
rather aberrant and unique open sutures in the dome of the latter=2C which =
diverges from all other so-called incipiently domed juvenile or subadult pa=
chycephalosaurids known to date)=3B moreover=2C they then note that *Pachyc=
ephalosaurus* itself is the largest roadblock to synonymizing these taxa in=
to it=2C such that the squamosal nodes are not even spikes but large knobs =
(with a broader circumference around the base than in *STygimoloch* OR *Dra=
corex* squmaosal horns=2C are rounded or bluntly accuminate=2C and much sho=
rter than the horns of the other taxa). They invoke metaplastic shange to r=
esult in this=2C along with erosion of the horns into knobs=2C but do not d=
emonstrate a parallel to test this hypothesis. Essentially=2C the paper tak=
es us on a faith-based argument that metaplasia + erosion DOES result in th=
is transformation=2C and ignore the functional concerns that contradict the=
 theory (secondary sexual seletion should result in a seeming reverse trans=
formation than they offer: knobs into spikes) for the sake of the fine hist=
ological work (which I do not have an issue with. The authors seem to push =
(from almost the first paragraph of the introduction) that the synonymy is =
real=2C and go about detailing the evidence FOR=2C but not AGAINST.

=A0 The reason I bring this up is that I should hope the currently pending =
work on chasmosaurine ceratopsids does not also fall into this argument=2C =
for I consider this work (fine) to be lacking in replicatability. Implicit =
in the argument is that the metaplastic transformation (and erosion thereaf=
ter) of the ornamentation in ceratopsids and pachycephalosaurids is used to=
 imply that a single taxon must arise from any development=2C and that beca=
use of this=2C the condition precludes the existence of multiple sister tax=
a (even coevals) with the same ontogenetic trajectory or metaplasticity dur=
ing growth. We are to assume that because they may be representative of a g=
rowth series=2C they represent the _same_ growth series of a single taxon. =
It beggars the imagination to assume that taxonomic diversity is so low for=
 a highly ornamented clade=2C unlike the observed specific variation only a=
mong Bovidae.

=A0 So even the authors note that *Pachycephalosaurus* impedes their own hy=
pothesis of its superior synonmy=2C and in this case=2C I agree based on th=
e data. Shall we expect the same from the *Triceratops* synonymy as well?

=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 disincli=
nation to do so." --- Douglas Adams (Last Chance to See)

"Ever since man first left his cave and met a stranger with a different lan=
guage 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 lo=
oking at things." --- Zapp Brannigan (Beast With a Billion Backs)

> Date: Thu=2C 29 Oct 2009 23:44:34 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: Even more concerning the Triceratops/Torosaurus deal
> ----- Original Message ----
> From: "GSP1954@aol.com"=20
> To: dinosaur@usc.edu
> Sent: Thursday=2C 29 October=2C 2009 17:23:37
> Subject: Re: Even more concerning the Triceratops/Torosaurus deal
>>At least one Torosaurus frill is known from Canada. So it is not possible
> for just T. prorsus to be north of the border while T. horridus was only =
> the U. S. growing up to be Torosaurus.
>>I have to wrap up the Princeton U Press dinofield guide right now=2C so m=
> try to figure out how to go on this without misleading the readers late n=
> year when the book comes out.
> As I stated before=2C all the questions and points so far raised have bee=
n previously considered=2C are answered in the upcoming papers=2C and most =
were answered in the various presentations that have been given on this. If=
 you have concerns about making sure your book is inline with what will be =
in the literature by next year=2C then perhaps email John Scannella=2C and =
see what he is prepared to say.
> D.
Windows 7: It helps you do more. Explore Windows 7.