Press Release for Wednesday, July 15, 2009
UNF Paleontologist Unearths Rare Sickle-Clawed Dinosaur in Utah Desert
Contact: Joanna Norris, Assistant Director
Department of Media Relations and Events
Dr. Barry Albright, a paleontologist and professor in the Department of Physics at the University of North Florida, along with a multi-institutional team of scientists, have discovered a new species of dinosaur belonging to an extremely rare group known as therizinosaurs (sickle-clawed reptiles) in Southern Utah.
The new dinosaur, dubbed Nothronychus graffami (no-thrown-EYE-kus GRA-fam-eye), represents the most complete specimen of a large-bodied therizinosaur yet discovered worldwide and is one of only three species of this rare type of dinosaur found to date in North America. The species is named for Merle Graffam, a resident of Southern Utah who discovered the skeleton and who also helped the Museum of Northern Arizona’s excavation team.
Other scientists involved in this research include Dr. Lindsay Zanno, John Caldwell-Meeker Postdoctoral Fellow in the Department of Geology at The Field Museum of Natural History in Chicago; Dr. David Gillette, Colbert Curator of Paleontology at the Museum of Northern Arizona in Flagstaff; and Dr. Alan Titus, paleontologist of Grand Staircase-Escalante National Monument, Bureau of Land Management.
“These are bizarre creatures,” said Albright. “Now, with the almost complete specimen we discovered, we have a much better picture of what they looked like and certain anatomical features confirm what was hypothesized previously on the basis of much less complete specimens from Asia.”
Therizinosaurs had very odd bodies. Their small heads had a keratinous beak like that of a turtle, and tiny leaf-shaped teeth. With a long neck and an enormous, barrel-shaped gut, these dinosaurs had stumpy legs and a short tail. But most impressive were their enlarged scythe-shaped hand claws that reached nine inches in length.
Therizinosaurs belong to a group of dinosaurs known as theropods or predatory dinosaurs, a group that includes such legendary members as Tyrannosaurus rex (T-rex) and Velociraptor. But scientists actually think therizinosaurs were plant-eaters, not predators. As part of this new discovery, the research team combined anatomical information from 75 other theropod species in an attempt to better understand the dietary evolution of the group.
“This discovery adds to the growing list of theropod dinosaurs that didn’t eat meat. We now know that there were several dinosaurs that belonged to the meat eating group, yet they were definitely plant eaters, just like Panda bears today are members of the mammalian order Carnivora, but they eat bamboo,” Albright said.
Nothronychus graffami is one of many new species of Late Cretaceous dinosaurs that have recently been uncovered in the remote and rugged Kaiparowits Plateau area of Southern Utah in and around Grand Staircase-Escalante National Monument. The burial ground of the nearly complete Nothronychus graffami skeleton was located in ancient marine sediments that would have been at least 60 miles from the closest shoreline 92.5 million years ago, which is the age of this specimen.
“One very interesting aspect of this discovery is that our specimen was excavated from sediments deposited in a marine environment, so the bloated carcass of this thing must have floated offshore, then sank in a nearly complete state,” said Albright, who has also discovered plesiosaurs, large predatory marine reptiles, in the very same sediments and location in Southern Utah over the last few years.
The age of this 92.5 million-year-old dinosaur is based on certain age-diagnostic species of mollusks found in direct association with the skeleton. “It’s extremely rare to be able to date a dinosaur as accurately as we have been able to date ours,” he said. “The ages of these fossil mollusks are known very accurately because of their association with volcanic ash beds in the same sediments that have been dated using a technique called radioisotopic dating.”
A special exhibit of the new dinosaur, called “Therizinosaur-Mystery of the Sickle-Claw Dinosaur,” will be on display at the Museum of Northern Arizona until September and will then be moved to the Arizona Museum of Natural History.