What makes the dinosaur named Leonardo stand out?

In 2000, a team from the Judith River Dinosaur Institute uncovered a 77-million-year-old duckbill dinosaur fossil, officially identified as Brachylophosaurus canadensis. They named the find Leonardo after graffiti found nearby: 'Leonard Webb loves Geneva Jordan 1916.' Leonardo wasn't fully mature; it was likely only 3 or 4 years old when it perished.

Gallery of Dinosaur Images

Leonardo's fossil was discovered embedded high in a canyon wall in Montana. Over nine weeks, 20 workers carefully extracted the fossil, with help from a demolition crew who used explosives to remove the 18-foot (5.5-meter) rock, weighing 6.5 tons (5.9 metric tons), equivalent to the weight of five Mini Coopers. The specimen was insured for $2.5 million, and for its world museum tour, Ford Motor Company created a full-scale 3-D model using rapid prototyping to transport instead of the actual fossil [source: Ford].

Why go through such effort and expense for a fossil? While Brachylophosaurus canadensis skeletons are rarely found, the significance of Leonardo goes far beyond its rarity. Unlike most dinosaur fossils that have been discovered, Leonardo still has preserved skin. Though not as soft as living creatures' skin, it's fossilized just like the bones.

Leonardo's fossilized skin also acted as a shield for its internal organs, from its heart to its stomach contents. So, when paleontologists study Leonardo, they're not simply examining a skeleton; they're analyzing a complete body. Studying this preserved body could provide insights into dinosaurs similar to how autopsies reveal details about humans.

However, there's a challenge. Conducting a traditional autopsy on Leonardo would ruin the fossil. Therefore, the researchers involved in the Leonardo Project have devised methods to study the dinosaur's internal structure without causing any damage, using non-invasive techniques.

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Mummified Dinosaur Fossils

Despite its remarkable preservation, Leonardo became a fossil in the usual way. Sediment covered its body, and minerals gradually replaced its tissues. However, something about Leonardo's burial was unique. Typically, soft tissues like skin, muscle, and cartilage decay before fossilization can happen. In Leonardo's case, possibly a thick layer of wet sediment shielded the body from scavengers and bacteria that decompose soft tissues, allowing its skin and internal organs to fossilize.

This unique preservation turned Leonardo into one of the rare mummified dinosaur fossils. At the time of its discovery, Leonardo was one of just four mummified dinosaurs ever found [source: Mayell]. The rarity of this find made it crucial to study the fossil without causing any damage.

To achieve this, researchers used one of the same techniques employed by doctors to examine human bodies without making incisions -- X-ray imaging. The team utilized a digital imager to capture over 40 X-rays of Leonardo's head and body, revealing insights into its interior. However, to achieve the necessary clarity to fully visualize the rock-encased organs, the researchers required a stronger radiation source than they could use in their lab. They transported Leonardo to a hangar at Johnson Space Center Ellington Field in Houston, Texas, where it was insured for $2.5 million. At the facility, they employed highly radioactive isotopes to penetrate deeper into the fossil and reveal its internal structures.

All of these X-ray scans culminated in a life-sized, 3-D representation of Leonardo's organs. Some of the discoveries include:

Leonardo is so incredibly preserved that scientists have even determined its diet. Inside its digestive system, they discovered:

The wealth of information extracted from this single fossil is astounding, which is why Leonardo has attracted so much media interest. A special titled "Secrets of the Dinosaur Mummy" on the Discovery Channel covers the research done with the fossil. Leonardo’s exceptional preservation has earned it a place in the Guinness Book of World Records as the most well-preserved dinosaur. However, this isn't just a media sensation—Leonardo represents a significant scientific discovery, with ongoing research that may reveal more in the future.