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Continuing the theme of years' past, here is a brief recount of this year's
Burpee Museum of Natural History's Paleofest. The Burpee Museum, based in
Rockford, Illinois, has recently been in the news for its discovery of a small
tyrannosaur, which may or may not be _Nanotyrannus_.
The specimen, nicknamed Jane after museum benefactor Jane Solemn, was partially
displayed this weekend. The right lower jaw is completely prepared and was on
display. It has, IIRC, 17 tooth sockets. Also prepared are some loose teeth,
a pathological pedal phalanx, and a tail vertebra. The museum has at least 50%
of the specimen, including near complete pelvic girdles, much cranial material,
at least one scapula-coracoid complex, and significant vertebral material.
Found inside the main jacket was also a single neck vertebra of an azhdarchid
pterosaur. The vertebra was recently prepared, and was on display. I didn't
measure it, but it appeared to be 25-30 cm in length. All of the material,
along with some other isolated stuff (including a _Pachycephalosaurus_ dome)
was collected from the Hell Creek Formation of SE Montana.
In the early news reports on Jane, Pete Larson and others were quoted as saying
that vertebral and hip fusion in the specimen shows that it is an adult. After
seeing the state of the specimen, it is clear that caution must be exercised
now. Much preparation and study is needed to determine what fusion is in fact
present. Unfortunately, due to the crowds, I was unable to spend much time
looking at and measuring the bones, but I was able to snap some photos. I am
willing to send scans to those who request them once I develop my film.
Tom Carr gave an excellent talk on his views on _Nanotyrannus_, discussing
several of the points he presented in his seminal 1999 JVP paper, which looked
at growth in _Albertosaurus_. From his _Albertosaurus_ study, Carr was able to
determine three general growth categories, and from this, and much personal
examination of the Cleveland Museum specimen, determined that _Nanotyrannus_ is
likely a juvenile _Tyrannosaurus rex_. Importantly, Carr has demonstrated that
the supposed prefrontal-parietal and parietal-frontal closed sutures, which
were observed by Bakker et al. (1988) as evidence of adulthood, are actually
open. Additionally, Carr has shown that a melange of synapomorphies are shared
between _Tyrannosaurus_ and the Cleveland Museum specimen, including a narrow
snout, wide basicranium, wide temporal region, and an upturned cranial margin
of the snout. Bakker et al. noted most of these features, but explained them
away due to convergence instead of common ancestry. !
us, Carr also discussed his view that none of the stated diagnostic characters
of Bakker et al. are valid, meaning that if the Burpee specimen is not a
juvenile _Tyrannosaurus_, it would require a new name.
Notably absent at Carr's talk was Robert Bakker, who was hanging around in the
lobby signing books while Carr was talking. I noted this as odd, since Bakker,
Pete Larson, and Phil Currie were recently mentioned in the Burpee Museum's
newsletter to have already agreed to be the lead authors of Jane's description,
which, according to the article, will be submitted to Nature or Science. This
team concerns me, as all three have been outspoken advocates of _Nanotyrannus_'
distinctness. Not that this is bad, but I hope that Carr and other scientists
who have voiced different conclusions based on their studies are consulted.
Other talks included an excellent presentation by Greg Paul, which focused on
his own art, avian evolution, and, of course, 2F. Paul also made some comments
on Garcia and Hutchinson's _Tyrannosaurus_ locomotion paper. Since HP Paul is
a listmember, I'll leave it to him to discuss his talk if he wishes. Mike
Novacek gave a talk Saturday evening on his adventures in the Gobi desert,
Allen Debus discussed the history of paleoart, and Wendy Taylor and kids from
Project Exploration gave a kids' talk on African dinosaurs. I was unable to
attend talks given by Larson and Bakker. I was also unable to attend Sunday
afternoon's debate between Bakker and Larson and Carr and Mike Henderson, who
argued over whether or not _Nanotyrannus_ is distinct. I do know that Bakker
called the Burpee's discovery "the most significant American discovery during
the past 100 years" during his talk, which may be somewhat of a hyperbole! :-)
You think he might remember illustrating that _Deinonych!
thing back in the late 1960's! :-)
Overall it was another enjoyable Paleofest weekend.
University of Chicago
Dino Land Paleontology-http://www.geocities.com/stegob
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