HOW TO BUILD A DINOSAUR

It's a Long Road from Discovery to Exhibition

By Richard Conniff

Paleontologists Pedro Mocho and Luis Chiappe study a model of a Diplodocus during reconstruction of the real thing at Research Casting International (Photo: Craig Cutler)

My latest, for National Geographic. Check it out in the September issue. Great photos by Craig Cutler.

What a strange thing it must be to become a fossil.  Say you live a full life for a Diplodocus dinosaur, swinging your enormously long tail across your Jurassic world for 70 or so years.  Then you die—but in such extraordinary circumstances that, against all odds, your bones are buried and transformed over time into stone. Mountains rise and wear away around you. Rivers come and go.  Glaciers rumble overhead. Your bones endure.

Even stranger, a hundred or more million years later, volcanic activity comes to dominate the area. When the superheated fluids eventually cool off and drain away, your bones have by some unknown process become green, the color of solidified seawater, highlighted here and there with red patches like roasted meat.  

And then the strangest turn of all:  To return to the surface after an absence of 150 million years, and be discovered, extricated, and reassembled by some unimaginable new species in a bizarre new world.

STEP 1: DISCOVER AND DIG

A team from the Natural History Museum of Los Angeles County first spotted the dinosaur called Gnatalie in 2007 as a single legbone revealed by erosion beside a bluff in southeastern Utah. What they found underneath brought them back to the dig site for nine more summers. The jumble of bones—Diplodocus, Camarasaurus, Ankylosaurus, Allosaurus, and others--had been swept together by the rivers of their day into a dinosaur logjam.

Even the Gnatalie going on display at the museum is not a single dinosaur, but combines parts from two or more individuals found at the site.  Gnatalie’s long neck and tail, and four sturdy legs, are characteristic of the genus Diplodocus. Paleontologists have yet to determine the exact species but suspect it may be new to science.

The name Gnatalie came unromantically from the tiny gnats that maddened team members that first year, forcing them at one point to wear fine-mesh mosquito netting improvised from brightly colored chiffon found at a local dollar store. They scheduled later digs for high summer, preferring the risk of dehydration and heat stroke to gnat bites.

Among other routine hazards of field work, mountain lions left their pug marks at the dig. Rattlesnakes sometimes sheltered under tarps. The tools of the trade, from dental picks to jackhammers, also required constant vigilance, to protect fossils and team members alike. On one occasion, a lightning bolt hit much too close. People scattered for shelter. At the top of the bluff, a lone juniper tree burst into flame.

But because the site was accessible, a long day’s drive from Los Angeles, the museum team saw it as a chance to show people how dinosaur science gets done, with volunteers, donors, and even high school students doing hammer-and-chisel work at the dig.  Planning dinner one night, the lead paleontologists did a headcount and realized they had 50 people in camp.  For some, it was the first time they’d slept in a tent.

The abundance of specimens also complicated the dig. “You're playing pickup sticks with a bunch of dinosaur bones,” says Alyssa Bell, a paleontologist at the museum. “They're all tangled and locked together.” At the start, the crew managed to keep their “jackets”—the protective plaster coating around a few fossils and some surrounding stone—at a scale the stronger workers could lift out by hand. But the bones demanded more.  A turning point came one day when the crew was planning “to jacket a couple of limb bones and get them out of the way.” Underneath, they discovered a massive section of spine still fused together. “I remember us just standing there scratching our heads and trying to figure out how on earth we're gonna get all these apart.”

An excavator had to clear away the face of the adjacent 50-foot-high bluff and some awkwardly placed boulders. Then the research team trenched around the block of stone containing the fossils, and dug under, leaving a temporary pedestal for support. With its heavy plaster jacket, the whole thing weighed a ton or more, requiring  heavy machinery for the lifting.

For another large specimen, a pelvis, “They had ropes on either side and teams of people rocking it back and forth,” says Stephanie Abramowicz, the museum illustrator at the dig, “and the moment it broke free, boom!” There was a crack of thunder. “It was very clear Gnatalie was speaking to us, released from the ground, ready to live another life.”

STEP 2: PREP BONES

But not quite yet.  The next stop for bones coming out of the dig was the museum’s prep lab in Los Angeles. Gnatalie specimens were challenging, says Doug Goodreau, who runs the lab, because the surrounding material was “cement-like compacted sand.” Dealing with any large specimen can require an angle grinder to chunk away excess stone, with sparks and stone chips flying. But an eye for the unexpected is also essential.

“Each jacket can be a quarry unto itself, with other elements that you find, a random tooth, or the femur of a Struthiomimus,” an ostrich-like dinosaur.  Work on the pelvis alone took the better part of a year. “But then something straightforward, like a small vertebra, can take a couple of months,” says Goodreau. “Or a tooth shows up that you can consolidate and stabilize and get out of the way in a week.”

As many as six preparators at a time worked to expose the fine details of Gnatalie’s bones, using tiny air-powered picks called zipscribes, and miniature sandblasters called air abraders. It sounded, says Goodreau, like a beehive buzzing.  The last bit of prepping Gnatalie was to fill flaws and gaps with an epoxy putty close to the color of the bone, but different enough to distinguish restored from original material. 

STEP 3: RECONSTRUCT SKELETON

Months later, in a small Canadian town on the north shore of Lake Ontario, 2600 miles from the museum, the bones lay in shallow wooden boxes, in a back room at Research Casting International (RCI).  Some bones rested on beds of foam, others on sand, each with a manila card detailing its place in the coming reconstruction. 

In a meeting room upstairs, staff from the museum and from RCI were working through details of the Gnatalie mount.  It would stand about 70 feet long, in the grand entry hall of a new wing of the museum. But at the moment it appeared that six feet of Gnatalie’s head and neck would poke through a wall into the next room over.  They debated alternative positioning, but every move seemed to be constrained by details already built into the architecture.  Too far one way, and Gnatalie’s head might miss key ceiling anchor points. Too far the other, and the tail would intrude on the space around an emergency exit. 

Despite what architects and designers imagined, Gnatalie was “not just a model you can make go any way you want,” says paleontologist Luis Chiappe, director of the museum’s Dinosaur Institute, who served from the start as leader (and head chef) at the dig.

The bones themselves imposed limits, But the possibility of hitting the wall did not seem to leave anyone flustered at the moment, insuperable obstacles being standard in paleontology.  Then, someone announced, a little meekly, that different design software programs have been miscommunicating: Gnatalie’s head would not poke through the wall after all.  

The meeting pushed on to the next obstacle: A large section of spine crushed during those 152 million years underground threatened to distort the entire mount.  In the end, Chiappe opted to have RCI scan those vertebrae and produce uncrushed 3-D-printed substitutes for a more natural look.  The real bones would be displayed below, as part of the exhibit’s message about the challenges of getting from dig to exhibition hall.

Thousands of decisions and months later, the RCI team set to work mapping parts and building corresponding steel structures to support them.  A thick-walled steel post for the pelvis and the back legs went up first.  Then came a horizontal steel armature following the natural curve of the spine, from the heaviest parts of the tail out, across a second post, into the base of the neck. 

The reconstruction took months of painstaking labor, and none of it was permanent. Instead, the sections of armature slid together, or apart, in a neat stub-and-socket system.  Steel holders attached each bone to the larger structure more firmly than in the living animal—but in such a way that any bone, or all of them, could be removed for repair or research.  It would take just a few turns with an Allen wrench, as if it were all an elaborate piece of ready-to-assemble household furniture.

When everything was complete, the bones and steel came down again, to be packed up in shipping crates, and trucked back across the continent to Los Angeles. There, on a plinth specially designed for this moment, the parts are now coming together again, more quickly this time.  Going on two decades since their first sighting, the dinosaurs blended together in this mount are rising up into the exhibition space they will henceforth dominate.

Gnatalie’s new life, as terror and teacher to our upstart species, is beginning at last.

Richard Conniff, a National Magazine Award winner, writes often about the natural world. His recent National Geographic articles cover pterosaurs and privately owned dinosaurs. His books include The Species Seekers and House of Lost Worlds.

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