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RE: Burpee Conference (LONG)



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Ken.Carpenter@dmns.org
>
> I am surprised that Holtz hasn't said anything about the Burpee
> tyrannosaur conference, so I'll force this hands ;-)
>
> There were several talks that were previously given at the Hill City
> conference, and several new ones mostly about Nannotyrannus being valid
> or a juvenile Tyrannosaurus. The most interesting in this regards was
> the CAT-scan data of the braincase of the holotype - definitely not a
> Tyrannosaurus.
> Take it alway Thomas.....!

Thanks, Ken!

Let's see, here's a brief summary:
After a brief introduction by Lew Crampton and Michael Henderson of the Burpee, 
and Mike Parrish of Northern Illinois University, we
got straight into the focus of the event: Jane the tyrannosaur. (I got drafted 
at the last minute to serve as a co-moderator for the
morning...)

Peter Larson continued to put forth his case for the reality of Nanotyrannus as 
a genus, based primarily on the presence of a higher
tooth count and a difference in tooth shape than Tyrannosaurus rex (and of the 
supposed "Tyrannosaurus X", Bakker's proposed second
species of the Big Guy), as well as the presence of a few different pneumatic 
structures (such as the lateral pneumatic foramen on
the quadratojugal of Jane, the Cleveland skull, and no other tyrants).

Currie (with Mike Henderson, Jack Horner, and Scott Williams as coauthors) 
showed that the change in tooth shape is in fact probably
just allometric, as is the purported difference in the glenohumeral joint. Phil 
still considers lancensis a distinct species, but
almost certainly the sister taxon to Tyrannosaurus, and thus (although he 
didn't say this out loud) it would be Tyrannosaurus
lancensis.

Tyler Keillor showed the work he did on the wonderful Jane head restoration. He 
presented some VERY persuasive arguments for a
varanid-like lip and gum arrangment in tyrannosaurs and other theropods. 
Basically, the line from the enameled to non-enameled tooth
surface is the gum line, but the gum line was well above the maxillary or 
dentary surface. When closed, even a T. rex may have had
hidden teeth and a lizardy-lip.  He also got several paleoartists to contribute 
their own different illustration of Jane.

Mike Parrish (with Mike Henderson and Kent Stevens) looked at the ontogenetic 
changes in the glenohumeral joint in tyrants.
Basically, they had proportionately longer humeri and greater lateral 
excursions as youngsters than as adults.

Kent Stevens (with Mike Parrish) showed via DinoMorph where the ontogenetic 
changes are in the tyrant skeleton, by morphing Jane
into Stan. Rather than simply holding the femur as a unit length, you used the 
body length as the unit and watched the changes in
the various parts. Also, he showed some of the sitting and standing sequences 
from the BHI meetings.

Thom Carr discussed his ongoing work in tyrannosaurid ontogeny and the 
application of cladistic algorithms as a test for these. (Ron
Tykoski is doing similar work with coelophysoids, as seen at last year's SVP). 
As no surprise, but nice to document, juveniles tend
to be placed basally to adults because they have not developed all their 
autapomorphic traits.

Hurum (with Currie and Badamgarav) discussed growth series of Tarbosaurus and 
Daspletosaurus.  Intriguingly (for me, at least), the
lacrimals of youngsters of these are more albertosaurine-like than the adult. 
Many beautiful specimens.

Erickson, Makovicky, Currie, Norell, Yerby, and Brochu's famous life history 
paper was presented, but none of them presented it!
Instead, Albert Prieto-Marquez did so, even though he works on tyrants one 
trophic level removed (i.e., hadrosaurids). By the way,
Jane was 11 when she died.

Then, lunchtime!

Stephen Hutt (glad I could finally meet him!) discussed the history of 
Eotyrannus' discovery, the weirdness of the anatomy (such as
its non-tyrannosaurid like pneumatic nasals), and the fact that he hadn't 
thought it was a tyrannosauroid at first. He did mention
he first wanted to call it "Fusinasius", but was convinced otherwise by his 
coauthors (there was at least one other proposed name,
but unless Hutt or one of his coauthors reveals it, I'm bound to secrecy). New 
material continues to be discovered.

Walter Stein (with Mike Triebold) discussed their tyrannosaurid nicknamed "Sir 
William". Most of what he presented was travelogue
and questions about the age of the specimen, but what has shown suggests that 
this (probably upper Judith River Fm.) specimen is a
tyrannosaurine close to the origin of Tyrannosaurus. Incidentally, this 
specimen was used in the Erickson et al. T. rex growth
curve.

Tom Williamson (with Thom Carr) discussed a specimen of T. rex from an 
artificial lake in New Mexico. Enough material is known to
document that it is indeed Tyrannosaurus rex, which appears to have ranged from 
Canada to Mexico.

Mary Schweitzer's talk (with Jennifer Wittmeyer and Jack Horner) was similar to 
her presentations at last SVP and at BHI: the
discovery of the medullary bone and soft tissue preservation in MOR 1125. She 
said that there will be new spectacular stuff at the
next SVP...

Larry Witmer and Ryan Ridgely's talk on CAT scanned tyrant skulls was damned 
good! They reinterpreted various features in the older
Nano and Sue scans (for instance, there are nasal turbinates in the "olfactory 
bulbs", which are actually olfactory chambers). The
biggest surprise, for these authors and the audience, was how different the 
Nanotyrannus was internally from the adult rex
specimens. The possibility of ontogentic change is not ruled out, but if so 
there were lots of changes in there.

Grant Hulburt updated previous work on encephalization of dinosaurs. T. rex EQs 
are well below recent birds, but among the highest
of non-maniraptoran dinosaurs. (Troodon, Bambiraptor, and Dromiceiomimus fell 
within Recent birds).

This Holtz guy, who was 40 years and 3 days old at the time of the 
presentation, discussed his latest phylogenetic analysis of
coelurosaurs with a focus on tyrants. I found two alternative arrangements on 
the major basal clades (either compys + [tyrants +
[ornithoms + maniraptorans]] or tyrants + [compys + [ornithoms + 
maniraptorans]]), two alernatives for Maniraptora (either the
arrangement in Dinosauria II or therizinos + [alvarez + [oviraptors + [birds + 
deinonychosaurs]]]). More importantly for these
talks, though, I recovered Dilong, Aviatyrannis, Eotyrannus, and Dryptosaurus 
as basal tyrannosauroids, and Appalachiosaurus as the
sister taxon to Tyrannosauridae. Also, Tanycolagreus came out as the basalmost 
tyrannosauroid.

Stephen Brusatte (with Paul Sereno, who is off in Niger doing archaeological 
[NOT a typo!!] work), did a nice metacladistic analysis
using CharacterSearch to see how two different phylogenetic analyses differ. 
The subjects were the Currie et al. (2003) and Holtz
(2004) tyrannosaurid phylogenies. He made our matricies jump through lots of 
different hoops, and showed (for instance) that my
characters record more structure but are more homoplastic, while Phil & co.'s 
preserved less structure but were more invariant.

Doug Nicholls (with William Harrison and Mike Henderson) discussed the 
palynological and paleomag dates for Jane. She seems to have
lived and died ~500 kyr before the K/T boundary.

We then had a nice buffet dinner at the Burpee.

Day Two:
Ken Carpenter summarized a lot of the recent work (much of it by him, with 
additional work by Matt Smith and Christine Lipkin) on
the evidence for predation by Tyrannosaurus rex. He was careful to point out 
that his assault on the obligate scavenger hypothesis
was not an attack on Horner and Lessem as people. Ken gave a great quote about 
one of their critiques of tyrannosaurid predation: in
response to the idea that 'we can't imagine how T. rex could have been a 
hunter', Carpenter said "Failure of imagination is not
evidence."

Bill Abler discussed serrations in tyrannosaurids and other meat eaters. He 
showed that serrations aren't necessarily just for
cutting, or for trapping meat, but also served to prevent breakage of the teeth.

Ralph Molnar's talk was, as he said, "on research I did 35 years ago, when Tom 
Holtz was 5 years old." Specifically, it concerned
biomechanics of the jaws of Tyrannosaurus and other tyrants, Allosaurus, and 
Ceratosaurus. By comparing lever arms and mechanical
advantages, he showed that the tyrannosaurids had more powerful bites than the 
Jurassic taxa; that Nano had a weaker bite than other
tyrants; and that Ceratosaurus had a stronger bite but smaller gape than 
Allosaurus. Ralph was pleased that computerized work by
Rayfield supported his conclusions.

Bakker was sadly not present, for personal reasons. Mike Henderson's 
presentation on the osteology of Jane supported the
identification as a juvenile Tyrannosaurus rex. There is a LOT of good material 
in this specimen, but sadly no braincase (yet!).

David Krauss gave a talk that some of us were wondering (from the abstract) if 
it was going to be a parody. It wasn't, but he did
recognize the humor in what he talked about. That is, Tyrannosaurus as a cow 
(or rather, Triceratops) tipper! He presented
biomechanical evidence that using realistic speeds, masses, and lengths, an 
adult Tyrannosaurus could push over a Triceratops, which
would have been vulnerable to attack before it got up. He also said that this 
was very speculative...

Darren Tanke started the pathology and taphonomy section by showing a subadult 
Daspletosaurus which was scavenged after it was
already partially decayed. Toothmarks were by another tyrannosaurid, but 
whether Daspletosaurus or Gorgosaurus cannot be determined.

Bruce Rothschild showed evidence that tyrants may have used their pedal claws 
in intraspecific combat. He showed that some of the
supposed "tooth punctures" on tyrant skulls might actually be claw punctures.

Eric Snively and Tanya Samman gave a pair of talks on tyrant necks (Eric on 
muscles, Tanya on bones). Both were very impressive, and
shows the University of Calgary as a good place for paleo grad students! They 
showed the ranges and limits of motions of the neck
system, and its probable role in siezing and manipulating prey. Also, Eric 
showed some great sequences of modern raptors attacking
and feeding.

Jim Farlow (with Holtz, Worthy, and Chapman) showed a data-rich presentation on 
the osteology of bipedal dinosaur feet in hopes
towards correlation with the ichnological record. Jim has assembled a database 
of metatarsal and digital measurements for NATs (aka
Non-Avain Theropods), Cenozoic ground birds, and ornithischians. In general, 
species tend to cluster together, but even closely
related genera may be in wildly different parts of plots. And, in contrast, 
distantly related large-bodied theropods tend to cluster
closer to each other than to more closely related small-bodied forms (perhaps 
as the result of physical constraints due to size).

Chistopher Vittore, MD (with Mike Henderson) examined the pathological pedal 
phalanx of Jane. He showed radiographs (as a
radiologist, he pointed out that an image made with X-rays is a "radiograph": 
NOBODY can "see X-rays"!!) and CT scans of the wound,
and got a diagnosis of a Brodie abscess.

Tracy Ford wrapped things up with a review of the tyrannosauroid record through 
time. While I don't agree with all his taxonomy or
systematics (i.e., the inclusion of Iliosuchus or Siamotyrannus in 
Tyrannosauroidea), he did show that tyrants spent most of their
history as small-bodied critters.

After this marathon session, it was time for lunch!

After lunch, there was an "ontogeny and systematics workshop", moderated by 
Mike Parrish, panelled by Phil Currie, Pete Larson, me,
and Mike Henderson, and attended by about half the conference goers. This was 
basically a question and answer period. Ken wrapped
things up by pointing out that, for whatever reason, people almost always say 
"T. rex" but never "G. libratus" or "D. torosus."  I
added that a new similar situation exists with "Mei long", which copy editors 
want to use even when I am only using genera for the
other critters in that sentence!

Overall: a strange but fun mix of professional presentations, amateur interest 
(esp. 3 boys who asked perhaps 70% of the
questions!), and low-key surroundings. If only the conference room wasn't so 
cold...

Anyone else have additional thoughts/comments to add?

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796