Queensland farmer stumbles onto 100 million-year-old sea monster

A farmer in Queensland's northwest has uncovered the fossilised remains of a giant marine predator that dominated Australia's great inland sea more than a 100 million years ago.

Robert Hacon told the Brisbane Times he was out poisoning some prickly Acacia while working on his property near the town of Nelia when he spotted some objects shining in the distance.

After a little digging he unearthed what turned out to be the 1.6m jaw of a Kronosaurus Queenslandicus, an 11m-long apex predator with a crocodile-like head and a body with four powerful flippers.

Mr Hacon has since donated the fossil to the Kronosaurus Korner Museum in nearby Richmond.

"The specimen represents the most complete mandible of a Kronosaurus Queenslandicus in the world, with most other examples being weathered, crushed or incomplete," the museum's curator, Dr Timothy Holland, was quoted saying.

"The scary thing is that this creature wasn't even an adult when it died — it still had a lot of growing to do."

The first recorded Kronosaurus Queenslandicus remains were discovered in 1899 but the most famous is a near-complete skeleton that resides in Harvard University's Museum of Comparative Zoology.