Artist’s rendition of Savannasaurus. (Travis Tischler/Australian Age of Dinosaurs Museum of Natural History)

In 2005, David Elliott was guiding his mob of sheep through central Queensland, Australia, when two fossilized bone fragments poking out of the soil caught his eye. As the eye in question was connected to the brain of a man who co-founded the Australian Age of Dinosaurs Museum, it was an organ better trained than most to spot ancient animal remains. Elliott returned to the spot with his wife, Judy, excited to show off what he believed were separate segments of a meat-eating dinosaur’s limb.

But Judy Elliott noticed something that her husband did not. She realized the bones fit snugly together, revealing not a limb but a single large toe.

It turned out they had found a heretofore undiscovered species of Australian dinosaur — an immense, four-legged creature that, at 40 to 50 feet long, was roughly the length of an 18-wheeler trailer. The Elliotts nicknamed the dino Wade, in memory of a close friend and fellow paleontologist.

With the help of the Queensland Museum, the Elliotts, who are both paleontologists, extracted Wade’s remains from the ground. This was not a simple task. The bones were locked in a large concretion of rock, which the excavators broke open by taking jackhammers to its preexisting cracks. All told, they removed 17 pallets of rock from the site, located at Australia’s Winton Formation, which dated to the beginning of the Late Cretaceous. The samples amounted to what paleontologist Stephen F. Poropat described to The Washington Post as “literally tons of material.”

Over the next nine years, museum staff and volunteers worried at the hard siltstone with pneumatic tungsten-tipped tools. As they revealed the dinosaur bones chip by chip, it was evident that Wade was unlike any other known Australian dinosaur. The animal’s skeleton indicated it was a type of long-necked, herbivorous animal called a sauropod — specifically, a titanosaur.

But Wade had several anatomical features that set it apart from other titanosaurs. Most obviously, it had hips of unusual size. “Early on, it became clear the pelvis was very different than had been found in any other sauropod in the world,” said Poropat, an expert on Cretaceous sauropods at the Australian Age of Dinosaurs Museum, to The Post by phone early Friday. Its five-foot hip girth meant the dinosaur was a “wide-gauge animal.”

Wade was also a rotund beast. The belly was extremely large, Poropat said, encasing an extensive gut and digestive system. Paleontologists like Poropat hypothesize that such large guts were home to bacteria that fermented chewed-up vegetation, akin to the rumens of modern-day cows and gazelles.

“If you’re going to be digesting tough plant matter,” he pointed out, “the bigger the better.”

In a new paper published in the journal Scientific Reports on Thursday, written by Poropat, the Elliotts and their colleagues, Wade earned its official name, Savannasaurus elliottorum. In the same study, the researchers also describe new physical features of Diamantinasaurus, a closely related titanosaur named in 2009. A brain case and shoulder bones of Diamantinasaurus were found in the same Winton Formation as Wade.

Reconstruction of Diamantinasaurus matildae (Travis Tischler/Australian Age of Dinosaurs Museum of Natural History)

It might seem unusual to have a few different types of multi-ton herbivores milling about at once, but Savannasaurus and Diamantinasaurus likely co-existed 98 million to 95 million years ago. “It’s actually a recurring theme,” Poropat said. In parts of the globe as distant as South America and Asia, bones from a few different species of sauropods have been found within proximate rocks.

Savannasaurus‘s fossils indicated that the dinosaur occupied a fairly primitive spot, near the base of the titanosaur family tree. Poropat and his co-authors viewed Wade’s unsophisticated characteristics, so to speak, as evidence that it was a close relative to species in South America. What’s more, as they argue in the paper, an ancestor of Savannasaurus and Diamantinasaurus probably marched across Antarctica to arrive on the Australian continent.

A hundred million years ago, Australia was much further south and firmly adhered to Antarctica. India had only slightly drifted away. There was almost certainly a connection between the Americas and Antarctica, at least temporarily, as oceans shifted around South America’s southern tip. During a period of global warming, while the poles heated up, a Savannasaurus precursor could have traversed the southernmost continent.

The journey would have lasted generations. “A couple of million years is not beyond the realm of reality,” Poropat said.

Savannasaurus and Diamantinasaurus fossils are currently on display at the Australian Age of Dinosaurs Museum. They are members of an exclusive crowd, two of the few dozen Mesozoic-era dinosaurs found in all of Australia.