Even when it's been dead for 110 million years, a shiver of fear might be expected on encountering the remains of a predator whose jaw is longer than many people.

Robert Hacon was spraying weeds on his property in western Queensland when he noticed something sticking out of the ground. Drought in the area had killed the grass and made previously hidden rocks visible. Hacon saw light reflecting off the bone, but “thought they were muscle shells so I drove away. Ten minutes later my curiosity got the better of me and I turned back.”

"I was kicking a few stones around with my feet ... I looked over a little bit and I thought 'oh my God what have I got here'," Hacon told the ABC. "It was so perfect. It was just like it had been killed a couple of weeks before and the crows picked it clean."

Credit: Kronosaurus Korner. Hacon returning to the scene of the find.

Hacon's discovery was the most intact Kronosaurus jaw ever found. The mandible (jawbone) is 1.6 meters (5 feet) long, but is thought to have come from a juvenile.

Kronosauruses were amongst the largest species of Pliosaurids, which dominated the seas during the Jurassic and Cretaceous Periods. Like most known Kronosaur fossils, Hacon's find is a Kronosaurus queenslandicus, a species that lived in the inland sea, which at the time occupied what is now central Australia.

Credit: Patricia Woodgate: Curator Tim Holland with the giant jawbone pieced back together.

Numerous finds in the area have led Richmond, a town with a population of 550 and located 1,500 kilometers (932 miles) northwest of Brisbane, to build the Kronosaurus Korner Museum. Hacon's mandible is the museum's most recent addition.

The museum's curator, Tim Holland, was understandably excited, telling the ABC: “It pretty much gives us the first really good, accurate idea of what a Kronosaurus jaw looks like."

Holland adds that the jaw is significant for being intact rather than its size, noting that a fully grown mandible would have been around 2.6 meters (8.5 feet) long.

"The jaws of the Kronosaurus was approximately twice the power of a large saltwater crocodile and we know from fossilised stomach content associated with other Kronosaurus specimens that the animals ate turtles, sharks and giant squids," Holland said. "The front section of the lower jaw has these really amazing long grooves that would accommodate teeth overhanging from the upper jaw. This hasn't really been well described before in any of the scientific literature so that is really exciting."

The museum forms part of Australia's Dinosaur Trail through areas rich in Jurassic fossils, although Kronosauruses were not dinosaurs.

Credit: Kronosaurus Korner. Part of the mandible with an Australian 50c piece in one of the slots where a tooth would have been.