Image Credit: Supplied

Washington, DC: In its past life, the skeleton of the allosaurus had been mounted in a running pose, its front legs raised, jaw open wide — the very picture of a prehistoric predator.

And before that — 150 million years ago — when it was a living, breathing creature struggling to raise its offspring and avoid predators and eke out a living amid the lush Jurassic landscape? Well, that’s a story that hasn’t really been told.

But when the National Museum of Natural History reopens its fossil hall next summer, it is the version of Allosaurus fragilis that visitors will finally get to meet.

“We wanted to show a different side of the animal’s story,” said Siobhan Starrs, project manager for the new exhibition.

“We really want visitors to think about the life cycle of this organism and how it would have been in many ways quite similar to organisms in the world today,” Starrs said. “We want you to feel connected to these stories ripped from the deep past.”

It’s a dramatic rebranding from the late 19th century, when this allosaurus was uncovered. It was the first near-complete skeleton of its species, with a massive skull, short clawed arms, long leg bones indicating powerful hind limbs, and a tail nearly as long as its body.

 We really want visitors to think about the life cycle of this organism and how it would have been in many ways quite similar to organisms in the world today.”

 - Siobhan Starrs | Exhibition manager 


Marsh, who collected the fossil, was one of the chief belligerents in the US’s early “Bone Wars”.

Little attention to detail

Paleontologists went to battle — and sometimes bribed, stole and sabotaged — one another in pursuit of ever bigger and more fearsome dinosaur species. The discoveries were given impressive names like “thunder lizard” (brontosaurus), and they were displayed in an exhibit at the museum known as “the Hall of Extinct Monsters". Mounts were often cobbled together with only a casual regard for scientific accuracy — Hatcher, the Smithsonian’s beloved triceratops, was a “Frankenstein” of fossils from completely different species.

Little was known then about the complex lives of these animals, and not many scientists seemed to care. One popular theory depicted dinosaurs as “degenerate,” a “dead end” of evolution — never mind that they ruled the Earth for nearly 200 million years, about a thousand times longer than Homo sapiens have been around. Traditional mounts and vintage illustrations often depicted them as lumbering creatures whose awkward bodies seem to defy all laws of biology and physics.

The skeleton of allosaurus are prepared for installation in the US National Museum of Natural History’s new fossil hall. Washington Post

“They were really almost like trophy specimens,” said Matthew Carrano, the museum’s curator of dinosaurs. The “monstrous” fossils might thrill museum visitors, he said, but held little appeal for researchers.

This view was reflected in the way specimens were displayed, in armatures that often degraded the fragile fossils and made it difficult to access them for scientific study.

'Skeleton crew'

“They had taken just a steel tube and rammed it through the centre of the fossils,” said Stuart Campbell, a project manager at Research Casting International who led the “skeleton crew” responsible for remounting the museum’s dinosaurs.

“I don’t know if they realised how special the fossils actually were,” Campbell said. “It was just the beginning of the age of knowledge about this.”

The nest of allosaurus. Washington Post

But then came the “dinosaur renaissance”. Several tantalising discoveries in the 1960s and ‘70s convinced scientists there was more to learn from these long-dead creatures.

Research on growth rates suggested that most dinosaurs were fast-growing, active and warm-blooded, like modern mammals. Analyses of dinosaurs’ distinctive bones demonstrated that they were direct ancestors of modern birds. Excavations of fossil footprints revealed that some species lived in herds, hunted in tandem, cared for their young. And the discovery of a gigantic crater off the coast of Mexico and a layer of buried extraterrestrial material around the world helped scientists realise that a catastrophic meteor impact — not biological degeneracy — likely led to the non-avian dinosaurs’ extinction.

The previous incarnation of the museum’s fossil hall, which opened around 1980 with the running allosaurus prominently displayed, partly reflected that evolving view. But dinosaur science was moving so fast the exhibit was outdated only five years after it was built, Carrano said.

Since the allosaurus was installed, researchers have discovered nests full of the crushed fragments of their empty eggshells, some of which will be modelled alongside the allosaurus in the new exhibit. They have uncovered prints from other theropod dinosaurs suggesting that the animals sat on the ground and monitored their nests, likely to protect them from predators.

The new mount is “cutting edge,” expert say, reflecting both the latest dinosaur science and state of the art practices for presenting skeletons. Washington Post

Life history

The 2014 closure of the old exhibit allowed Smithsonian scientists to get their first good look at the dinosaur in decades, revealing details about the injury to its shoulder blade and other incidents in its life history. Carrano and his colleagues are still sifting through that data, which they hope may give them insight into the animal’s age when it died and whether it was male or female.

After spending so much time with the skeleton, getting to know its bumps and bruises, imagining where it obtained them, “you do kind of connect with [it] as an individual,” Carrano said. “I don’t think of it as an allosaurus, right? I think of it as our allosaurus.”

On a recent morning, he and Starrs stood by as Campbell and his “skeleton crew” carefully installed the allosaurus in its new display.

Headfull

The backdrop is painted with stout cycads and arching ferns, to give visitors a sense of the dinosaur’s home environment. Posed beside a gigantic diplodocus and beneath towering ancient trees, the allosaurus doesn’t look so imposing. You might almost forget that it could easily fit a whole human head in its gaping carnivore’s mouth.

Almost.

The new mount is “cutting-edge,” Starrs said, reflecting both the latest dinosaur science and state of the art practices for presenting skeletons. Rather than hold the mount together using rods plastered directly onto the fossils, Campbell’s team has built an armature that grips the bones in place, as though they were diamonds in a necklace setting.

“You have to cradle each one,” Campbell said. “It avoids any stress.”

The new display also allows researchers at the museum to remove individual bones for research without dismantling the whole fossil, so staff won’t have to wait several decades to learn something new about their allosaurus.