46 DISCOVERMAGAZINE.COMAMAN
DAKELLEY^ (
2 )Most Massive T. Rex Ever
Died Old and Battle-Worn
BY GEMMA TARLACHi
“It’s a big honkin’ animal.”
That’s how College of Charleston
paleontologist Scott Persons describes
the fossil that happens to share his name.
“Scotty,” named for a celebratory bottle of
scotch cracked open to toast its discovery,
is the biggest Tyrannosaurus rex in the
fossil record — and the most elderly.
The first bits of the animal surfaced back
in 1991 in southwestern Saskatchewan,
Canada, encased in iron-rich, extremely
hard sandstone, which made excavation
difficult and time-consuming. At the time,
Persons notes, “no one knew how much of
the animal was there, or how big it was.”
It would take decades for researchers to
excavate and prepare the bones for study.
In fact, it wasn’t until March, when Persons
and colleagues published the first fullanalysis of the animal in The Anatomical
Record, that its enormity could be fully
appreciated.
At an estimated 19,500 pounds and with
a length of nearly 43 feet, Scotty is kind of
a big deal. It’s larger than the most famous
tyrant king fossil, Sue, who currently
resides at Chicago’s Field Museum. Sue is
a couple feet shorter and about 800 pounds
lighter.
“You couldn’t say this thing rivals
Sue until you had all the numbers,” says
Persons. But he is quick to note that size
isn’t everything when it comes to the
mightiest of apex predators. Scotty is an
impressive 65 percent complete, but, at
about 90 percent, “Sue is still the most
complete. To be fair, in terms of scientific
value, that counts for more.”The most significant thing about
Scotty may be its advanced age. Coauthor
Gregory Erickson studied growth pat-
terns preserved in Scotty’s bones, similar
to tree rings, to determine the animal was
more than 30 years old when it died some
66 million years ago. Says Persons: “Most
T. r e x e s die when they’re teenagers.” (For
comparison, paleontologists believe Sue
lived to the ripe old age of 28.)
“Scotty lived a hard-knock life,” Persons
adds, naming a long list of animals, from
club-tailed ankylosaurs to another hun-
gry T. r e x, that could have fought the apex
predator. “Little kids tell me all the time
they want to be a T. r e x and I say, ‘No, no,
no! T. r e x e s had an awful life!’ You’re trying
to make a living and find your next meal
and you’re getting beat up by everybody.”
Scotty had the scars to prove that. The
animal’s remains include a broken rib, a
nasty, lingering infection in its jaw and a
massive compression injury on its tail that
may have been the result of chomping by
another T. r e x.
While Persons is thrilled about present-
ing his namesake to the world, he believes
Scotty won’t hold the heavyweight cham-
pion title for long.
“I can guarantee you that, in generations
to come, it won’t be the biggest,” he says.
“T. r e x was around for millions of years,
[and] we probably haven’t found the full
extent of the range. There’s no way that
we’ve happened to stumble across the
largest member of the species.”Paleontologist Scott Persons (above and top
left, with “Scotty” — no relation) believes the
65-percent-complete tyrannosaur, the most
elderly and the most massive in the fossil record,
won’t be the biggest T. re x ever found.