A fossilized skeleton believed to be the largest specimen of a Tyrannosaur ever unearthed was found this summer by a field crew headed by J. Keith Rigby, a University of Notre Dame paleontologist. The fossil, which has been only partially excavated, lies in a vast dinosaur graveyard in northeastern Montana near the Fort Peck Reservoir.
According to Rigby, the fossil is nearly complete and is either a Tyrannosaurus rex or something very much like it. Certain aspects of the anatomy are different than the 15 or so known skeletons of T. rex, he says, and it appears to exceed all measured skeletons of the dinosaur. "What we do know is that it's the largest carnivore on the planet.," he says.
Rigby reports that the pubis, one of three main bones in the pelvis, measures at least 52 inches, compared to 48 inches in the largest known T. rex. The femurs or thigh bones, which paleontologists normally use to estimate the size of dinosaurs, await excavation at the site.
Unfortunately, former owners of the cattle ranch on which the fossils were found entered the site and began digging up the bones that remained in the ground, including the skull. Contending they still own the land, they evidently planned to sell the fossil to a private collector.
On Sunday (Sept. 14), Federal law-enforcement officers descended on the site, which a title search indicates lies on land now owned by the U.S. Dept. of Agriculture's Farm Service Agency, and forced the former owners to vacate the premises.
Rigby and the Earthwatch Institute, which funded a major part of the research, had planned to complete the excavation and receive independent corroboration of the fossils before jointly announcing the discovery, but the events unfolding on the site have forced their hand. Rigby had temporarily closed the site in August and returned to Notre Dame to begin the fall semester.