Montana's Famous "Mummified" Dinosaur
Photo courtesy of the Judith River Dinosaur Institute
"The best-preserved dinosaur remains in the world
belong to ‘Leonardo’, a 77 million year old Brachylophosaurus.
Around 90% of the body is covered with fossilized soft tissue."
Guinness World Records L.T.D.
A "treasure" is discovered . . .
Leonardo was discovered near Malta, Montana on July 27, 2000
when Dan Stephenson of Minot, North Dakota noticed the
exposed mid-section of Leonardo’s tail and part of its pelvis in a
large channel sandstone deposit within the Judith River
Formation. This particular formation is made up of sediments
(mud, sand) that were deposited during the late Cretaceous
Period when the environment in eastern Montana was similar to
that found today in the Mississippi Delta region.
More than just bones . . .
This photo, taken in Malta, Montana, shows Leonardo along with
paleontologist Nate Murphy, head of the Judith River Dinosaur
Institute. What’s sets Leonardo apart from other dinosaur
fossils is that 90 % of his skeleton is covered with (fossilized)
tissue, including skin, scales, muscle, foot pads . . . Even his last
meals, which included ferns, conifers, and magnolias, were
fossilized in his stomach. Minerals have replaced the soft tissue
and stomach contents just as they do when wood becomes
“petrified”. In addition to being a 77 million year-old “mummy”
that will keep scientists busy for years, Leonardo is one of only
four brachylophosaurus* specimens uncovered to date, and he is
the first fully articulated sub-adult ever found. Leonardo is
believed to have been 3 or 4 years old when he died.
Nature’s takes it course . . .
When an animal dies, decay bacteria move in to begin
consuming the soft tissue. Scavengers show up to nibble on the
flesh and flies stop by to lays eggs in the carcass. As maggots
hatch from these eggs they help consume the rotting flesh.
Usually within a matter of weeks or months most of the soft
stuff has decomposed. The bones, which may take years to be
weathered away, often become scattered by wind, water, or
Rare circumstances . . .
If a dinosaur died in just the right place, possibly along a river or
on a delta, it might have become buried by sediment. If this
happened soon after the animal died its body would have been
somewhat protected from the elements, and it might have
become fossilized. However, it is even more unusual to find a
dinosaur fossil that includes anything but bones, indicating that
burial rarely happened before the soft tissue rotted away. In
fact, Leonardo is one of only four dinosaur fossils ever found to
be classified as a "mummy" because of the amount of soft tissue
that was preserved. Unfortunately, the other three were
uncovered in the early 1900s, when excavation and preservation
techniques were not as advanced as they are today.
Good news! . . .
On April 16, 2005 the Montana
Legislature passed a bill that will provide $500,000 “seed
money” to build a Great Plains Dinosaur Park in Malta, Montana.
Without the funds, it is possible that Leonardo would have been
moved to another state where scientists could study him. The
Judith River Dinosaur Institute hopes to raise another $1.5
million to build the center. Currently Leonardo, and several
other important dinosaur discoveries, are being stored at the
institute’s “field station” (a converted tire garage in Malta).
*Brachylophosaurus: a species of duck-billed
Terms: petrify, delta (of a river)