Paleontologists have discovered a Tyrannosaurus rex and its very complete skull in northern Montana. The find, which paleontologists estimate to be about 20 percent of the animal, includes vertebrae, ribs, hips, and lower jaw bones.
The team discovered the T. rex during an expedition to the Hell Creek Formation—an area world-famous for its fossil dinosaur sites. Two paleontology volunteers from the University of Washington’s Burke Museum of Natural History and Culture, Jason Love and Luke Tufts, initially discovered pieces of fossilized bone protruding from a rocky hillside.
The bones’ large size and honeycomb-like structure indicated they belonged to a carnivorous dinosaur. Upon further excavation, the team discovered the T. rex skull along with ribs, vertebrae, and parts of the jaw and pelvis.
15 years old, 66-68 million years ago
T. rex was one of the largest meat-eating dinosaurs to ever roam the Earth. Measuring an average of 40 feet long and 15 to 20 feet tall, T. rex was a fierce predator with serrated teeth and large jaws. Fossil evidence shows it ate other dinosaurs like Edmontosaurus and Triceratops, with crushed bones from the animals even showing up in its fossilized poop.
T. rex lived about 66–68 million years ago in forested river valleys in western North America during the late Cretaceous Period.
The newly discovered T. rex is nicknamed the “Tufts-Love Rex” in honor of the two volunteers who discovered it. The skull is about 4 feet long and weighs about 2,500 pounds in its protective plaster jacket.
Excavation in the field revealed the right side of the skull from base to snout, including teeth. Paleontologists believe it is very probable the other side of the skull is present, but will need to carefully remove the rock surrounding the fossil before they can determine its completeness.
Based on the size of its skull, paleontologists estimate this dinosaur is about 85 percent the size of the largest T. rex found to date. At the hips, the T. rex would have been nearly as tall as a city bus, and as long as a bus from tail to head. Based on the size of the skull—a good indicator of T. rex age—the team estimates the dinosaur was about 15 years old when it died. Adult T. rex lived up to 25-30 years.
The Tufts-Love Rex is 66.3 million years old. T. rex lived at the end of the Cretaceous Period, 145–66 million years ago, and became extinct during the Cretaceous-Paleogene mass extinction 66 million years ago. The paleontologists could determine that the Tufts-Love Rex lived at the very end of the Cretaceous because it was found at the bottom of a hill; a rock layer at the top of that hill marks the Cretaceous-Paleogene mass extinction.
A very rare find
Although arguably the most iconic and well-known dinosaur, T. rex fossils are rare. This remarkable find is one of only about 25 of this level of completeness. The skull is the 15th reasonably complete T. rex skull known to exist in the world. Next summer, Burke Museum paleontologists will search for additional parts of the dinosaur at the site.
More than 45 people helped excavate the T. rex over the course of a month this summer. The team was collecting fossils in the area for the Hell Creek Project, a project examining vertebrates, invertebrates, plants, and geology of the area to learn more about the final 2 million years of the dinosaur era, the mass-extinction event that killed off the dinosaurs, and the first 1.5 million years post-extinction that gave rise to the age of mammals.
Source: University of Washington