 The
T. rex known as Jane is a remarkably-preserved example of a juvenile
of the type which has just been placed on display June 29, 2005
at the Burpee Museum of Natural History in Rockford, Illinois. This
specimen was discovered through the efforts of a 14 member staff
and volunteer group from the museum who were prospecting for surficial
material in the 66 million year old Hell Creek deposits in the Badlands
of southeastern Montana in June of 2001. On the last day of field
work evidence of a leg bone and a toe bone was uncovered. A return
expedition with the appropriate permits from the Bureau of Land
Management in June-July of the following year led to recovery of
a 50% complete, mostly articulated skeleton of what was ultimately
determined to be a juvenile T. rex, the most complete ever found.
At first, thoughts of some researchers revolved around the skull
of a small Tyrannosaurid housed in the Cleveland Museum of Natural
History. After three years of painstaking preparation and research,
the diagnosis as a juvenile T. rex was made, making Jane a spectacular
find to have been made, collected, and prepared by a small museum
in rural Illinois. Dr Gregory Erickson of Florida State University
determined Jane’s age to be eleven, a mere adolescent. His
research has shown T. rex to undergo a growth spurt which slowed
down by age 17 or 18, with most living no longer than 28-30 years.
As an adolescent, Jane has some remarkable characteristics:
- Compared
to an adult, Jane’s arms are proportionately larger, with
a more open shoulder joint, suggesting she may have been able
to have far more freedom of movement.
- While
the number of teeth in an adult varies somewhat, Jane has 12 more
teeth than the average. Evidence that the number of teeth declined
with age has been mounting.
- Like
a puppy, Jane’s feet appear overly large in proportion to
her body. She presumably would have “grown into” them
had she lived to adulthood.
- Jane’s
legs are also proportionately longer than an adult. Some researchers
have proposed that the juveniles may have been the pursuit predators
of a pack of hunting T rex.
- Jane
was about 7.5 feet high at the hip, as opposed to 12 feet for
an adult. At 21 feet in length, she was only half the average
adult length of 40 feet. Her estimated weight was only 1500 pounds,
as opposed to 11,000 pounds for a full-grown adult.
A visit
to this museum would be well worth the effort to see such a fine
example of a juvenile T. rex. They plan on holding a Tyrannosaurid
symposim in mid-September of this year. The upcoming symposium,
“The Origin, Systematics and Paleobiology of  Tyrannosauridae”
will be held September 16-18. They will have 30 renowned paleontologists
scheduled to present their ongoing tyrannosaur research. Some of
the presenters include Dr. Philip Currie, Dr. Thomas Holtz, Dr.
Bob Bakker, Dr. Thomas Carr, Dr. Greg Erickson, Peter Larson, Dr.
Scott Sampson, and many more. Talks will begin around 9:00 AM on
Friday, Sept. 16 and will finish on Saturday afternoon. They will
also have a buffet/mixer and silent auction at the museum Friday
night. Please check www.burpee.org by clicking thier home page image
to the right, for registration forms, list of presenters and location.
Also
see: Dinosaur Fossils
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