dinosaur museum

July 2020 Newsletter

FROM THE EDUCATION DESK

It is so wonderful to be open and greeting our visitors again. I hope you have been able to join us at the museum during this last month. Even though we had to cancel our Outdoor Family Day in June, we are having our Outdoor Summer Fun Day on July 11th. It has been a hard few months for everyone and we hope to see you all here to join in the fun.

FYI: Utahraptor

In 1991, Utah State paleontologist Jim Kirkland and his crew were excavating a bonebed outside Moab, Utah which had dinosaur fossils in it dating back 125 million years. Kirkland found the front of a jaw from a theropod, the class of dinosaurs containing such meat-eaters as T.rex. Later that same field season, they found a sickle claw while digging. The shape was unmistakable. The recurved claw was just like the foot claw of dinosaurs like Deinonychus and Velociraptor, only this one was much larger. “It was twice as big as the same claw on Deinonychus,” Kirkland said.

That claw would become the single fossil that characterized a new animal, Utahraptor ostrommaysi.

In 1975, Brigham Young University paleontologist Jim Jensen collected a batch of theropod bones from a nearby site called Dalton Wells. They were not recognized as Utahraptor bones until years later when Kirkland saw the similarities and the fossils were more fully prepared. These bones made a big difference to Kirkland’s team. It turned out to contain dozens of Utahraptor bones which was enough to put pieces of multiple skeletons together to create a better version of the dinosaur. “Utahraptor is the largest dromaeosaur in the family,” says University of La Rioja paleontologist Angelica Torices. It is estimated to have stretched 23 feet long and weighed more than 600 pounds. “The claws on the hand seem to have been more specialized for cutting than other dromaeosaurs,” Torices says, and the teeth at the front of the lower jaw appear to angle forward farther than in other raptors.

By studying various dinosaur teeth, Torices found that carnivorous dinosaurs used a “grip and rip” feeding style. The dinosaurs would bite and pull backward, letting the serrations of their teeth do the work. Utahraptor probably ate in the same way.

In 2001 a graduate student spotted a bone in an area of Early Cretaceous rock layers in Moab. It turned out to be more Utahraptor bones. When they dug deeper they discovered dozens of bones from multiple individuals, from yearlings to full grown adults, encased in a nine-ton block of Cretaceous quicksand. It took years of work to excavate and transport the block so they could study it more. The block is still being studied. The bones are very tiny and they have found skulls from 3 yearlings, five juveniles and one adult. The front of the upper jaw of a baby Utahraptor is about the size of a penny!

Adult Utahraptors were much bulkier animals than Velociraptors. The limb bones are 50% more massive than the same sized Allosaurus bone. Recent studies suggest this dinosaur would have been covered in feathers.

In 2018 Utahraptor was made Utah’s state dinosaur and Allosaurus was shifted from the state dinosaur (from which he was) to become the Utah state fossil.
Information: Riley Black……smithsonianmag.com

Geri Lebold
Education Director

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