dinosaur museum

March 2020 Newsletter


It is really cold outside and this our snowiest month of the year! So I am going to “Think Spring” and hope for the best!!! Really looking forward to the first day of Spring on March 20th!

March Trivia: Each year March and June end on the same day of the week. March was named for the Roman God of War and NASA astronaut Scott Kelly returned from space after one full year, setting a new record for the longest uninterrupted trip to space.


Allosaurus jimmadseni

A new species of dinosaur has been described in a paper published on January 24, 2020 in the scientific journal PeerJ. The first specimen was discovered on July 15, 1990 in Dinosaur National Monument in northeastern Utah by George Engelmann of the University of Nebraska, Omaha. The skeleton block was so heavy it required the use of explosives to remove surrounding rock and a helicopter to fly it out. The head of the skeleton was missing but was found in 1996 by Ramal Jones of the University of Utah using a radiation detector. The skull of A. jimmadseni is more lightly built than its later relative Allosaurus fragili suggesting a different feeding behavior between the two. It required seven years to fully prepare all of the bones of A. jimmadseni and much of the preparation was done by Scott Madsen and Ann Elder with assistance from Dinosaur National Monument volunteers and students at Brigham Young University. This huge carnivore inhabited the flood plains of western North America during the Late Jurassic period, between 157-152 million years ago, making it the geologically oldest species of Allosaurus, predating the more well-known state fossil of Utah, Allosaurus fragilis. Years of excavation work along with a large amount of research kept A. jimmadseni from being officially classified until now. The name Allosaurus means “different reptile” and “jimmadseni” honors Utah State Paleontologist James H. Madsen Jr. who studied & excavated tens of thousands of Allosaurus bones.

This illustration shows a pack of the newly discovered Allosaurus jimmadseni attacking a young sauropod. (Image: © Todd Marshall)

This remarkable dinosaur is described based on two complete skeletons. It was approximately 26-29 feet long and weighed around 4000 lbs. This was a two-legged dinosaur with long forelimbs and sharp claws that were likely used for grasping prey. It had a large head with 80 sharp teeth and was the most common carnivore in its ecosystem.

“This study illustrates the importance of continued paleontological investigations on public lands in the west.” said Brent Breithaupt, BLM regional paleontologist. “Many more exciting fossils await discovery in the Jurassic rocks of the American West”, said Daniel Chure co-lead author of the study.

Geri Lebold
Education Director

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