Jane, A Very Complete Juvenile Tyrannosaurus rex
at the Burpee Museum of Natural History in Rockford, Illinois

Tyrannosaurus rex

Phylum Chordata, Class Sauropsida, Superorder Dinosauria, Order Saurischia, Suborder Theropoda, Family Tyrannosauridae

Geological Time: Cretaceous

Fossil Site: Hell Creek Formation, Badlands of Southeastern Montana

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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