May 21, 2016

By Emily Chung

Fossil found by nuclear physicist goes on display at Canadian Museum of Nature in Ottawa

Once upon a time, a scrappy horned dinosaur with a nasty bone infection died on the banks of a coastal river in Montana.

Seventy-six million years later, a nuclear physicist out for a walk among the steep, scrubby hills, stumbled across her fossil remains. And now "Judith" has found a new home at the Canadian Museum of Nature in Ottawa, where scientists have confirmed that it is the first of its species ever discovered.

Scientists don't know whether Judith was male or female — it was named after the Judith River rock formation where it was found by Bill Shipp, says Jordan Mallon, a paleontologist at the Museum of Nature who led the analysis of the fossil.

"He was looking for sort of a place to get away to do hunting and fishing," Mallon said.

Beginner's luck

Knowing there were fossils in the area, he decided to go for a walk about the property.

"Little did I know that the first time I went fossil hunting I would stumble on a new species," he recalled in a news release.

He spotted what turned out to be one of Judith's leg bones sticking out of a hill.

But in the end, the team managed to find half a skull, along with parts of the dinosaur's front limbs, hind limbs, hip bones and parts of its backbone — enough for paleontologists to later get a good idea of what Judith was like.

The dinosaur would have been about 4.5 to six metres long and weighed around three or four tonnes — "basically somewhere between a rhino and an elephant in size," Mallon says.
Thrilling frill

Like other horned dinosaurs, it had a massive head with a big, spiked frill and horns. But their unique configuration identify it as a new species, a missing link between earlier horned dinosaurs with outward-pointing spikes on their frill and later horned dinosaurs with forward curling spikes, the research team found.

Judith had a narrow, pointed beak that it would have used to munch on low-growing shrubs, leaves and twigs.

And it had four stout limbs, but it likely only walked on three — the dinosaur suffered a bone infection in its left humerus or upper arm bone, scientists discovered.

"It's just really gnarly looking, and especially toward elbow, there's this big hole that's opened up in bottom of it that would have served to drain the infection," Mallon said. "And probably it rendered that left forelimb useless for walking."

The researchers also found signs that Judith suffered a similar injury and infection in its frill, including a hole similar in size and shape to one of its horns. That has led Mallon to speculate that Judith was gored by another member of its species, although there isn't really good evidence to support the theory. What scientists do know is that horned dinosaurs lived in herds and likely had a social hierarchy within their group.

"It might be that these were two rivals competing for dominance," Mallon said.

"She was of robust constitution, I like to say — very resilient," Mallon said.

Mallon first learned about Judith when Shipp visited Ottawa for a conference in February 2015 and arranged to meet with him. Shipp wanted to find Judith a home at a museum and was impressed with the Canadian Museum of Nature's collection of horned dinosaurs.

He was impressed by the careful way Judith was collected, with all the key data intact, such as the exact position of each bone with the rock layers – important information that is often lost when amateurs collect fossils.

But it decided to purchase Judith for roughly the cost of her excavation, about $350,000.

"This was a very, very fair price as far as I'm concerned," Mallon added.

He and his team spent the next year studying the new species, and have published their findings in the journal PLOS ONE.