Tufts-Love T. rex was about 19 years old when it died

May 10, 2019
Cathy Morris
thomas carr stands next to the t. rex skull while studying it closely

Paleontologist Thomas Carr (Carthage College) researching the Tufts-Love Rex skull in the Burke Museum fossil prep lab.
Photo: Cathy Morris/Burke Museum

Paleontologist Thomas Carr, a leading expert on Tyrannosaurus rex, is visiting the Burke Museum from Carthage College in Wisconsin to take a closer look at Tufts-Love Rex. It’s the last day of his week-long visit to Seattle and he is quietly crouching below the massive T. rex skull using a headlamp to illuminate the details of its anatomy.

Carr is wrapping up a week of looking at approximately 2,000 features on the 66.3-million-year-old fossil to describe whether they show juvenile or adult condition.

Juvenile T. rex bones start out with a smooth surface and then become more roughened and textured as the animal ages. Documenting these growth changes will help to shed light on how this animal grew and matured along with ultimately answering some big evolutionary questions.

"Growth is a window into evolution,” said Carr. “No one has ever sat down to decode the full growth code of T. rex, most focus on only one aspect or set of features."

He believes that the Tufts-Love Rex was a young adult and at least 19 years old when it died. “There is a crest at the top of the skull that is absent in baby T. rex and the Tufts-Love Rex has the start of this crest,” said Carr. This age prediction can be tested by taking a histological section of a bone, such as a belly rib since leg bones are not preserved in the specimen, and counting the annual growth lines to obtain its chronological age.

"The Tufts-Love T. rex is a very important transitional specimen that helps fill in gaps between juveniles and adults. It's remarkably complete and shows excellent preservation.”

thomas carr crouches below the t. rex skull while studying it closely

Thomas Carr crouches below the Tufts-Love Rex skull while studying its features.
Photo: Cathy Morris/Burke Museum

The phrases “remarkably complete” and “excellent preservation” don’t get used that often when it comes to dinosaur fossils. Conditions have to be just right to preserve the animal in the first place then its remains have to withstand millions of years of geologic forces.

Thankfully all bones are accounted for in the skull, even a thin and delicate bone called the epipterygoid that is not often preserved in fossils, making it one of the best-preserved T. rex skulls in the world.

thomas carr stands next a T. rex rib bone in the fossil prep lab

Thomas Carr with other Tufts-Love Rex fossils in the Burke Museum fossil prep lab. 
Photo: Cathy Morris/Burke Museum

"This stands out amongst all of the specimens I've seen recently,” said Carr. "We're very lucky this T. rex was found on federal land and that the museum found it. It’s incredibly valuable to have a specimen of this level of scientific importance accessible to researchers around the world.” 
 
And it will remain accessible even once it goes on display in the new Burke Museum paleontology gallery when the museum opens in October—a key factor for museum leaders like Greg Wilson, Curator of Vertebrate Paleontology, during the exhibit planning process. “We want more researchers to come and study our fossils,” he said. “There are many ways that a specimen of this quality can impact science, some of which we haven’t even thought of yet.”
 
Natural history museum collections, like what we have at the Burke, provide glimpses of past and present life, and can help us predict what the world might be like in the future. 
 
“Researching museum specimens like this is an important part of keeping knowledge alive," Thomas said while wrapping up for the day. “This specimen will significantly enhance our understanding of T. rex.”
Close up of the teeth and snout of the T. rex as thomas carr stands in the background

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What’s happening with the T. rex right now? The team is currently removing the rest of the rock from underneath the skull to prepare the skull for display in the New Burke when the museum opens this October. See a sneak peek of the new paleontology gallery on our project website.

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