Bones of the sauropod named Austrosaurus mckillopi date from the Early Cretaceous period (104-102 million years ago) and were first discovered in 1932 on Clutha sheep station in Queensland.
However, attempts by palaeontologists to relocate the site during the 1970s and 1990s failed.
Stephen Poropat, a palaeontologist at Swinburne University of Technology in Australia, became intrigued by the mystery of the lost site when he studied the bones currently in storage at the Queensland Museum.
In 2014, he contacted Tim Holland, former curator at Kronosaurus Korner marine fossil museum, about relocating the site.
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Three digs at the site between 2014-2015 uncovered six rib bones, which when placed with the vertebrae found in the early 1930s created a more complete picture of the dinosaur.
"The most exciting realisation was that portions of the ribs were embedded in the rock surrounding the left side of the backbones," Poropat said.
"This means that the carcass of Austrosaurus came to rest on its left side, and it was not shifted much after it died allowing the bones to stay close to a life position," said Poropat.
Because of its age, Poropat said, Austrosaurus might reveal something about the evolution of other sauropods in Australia.
"The sauropods commonly found in the Winton area, south of Richmond, lived five to ten million years after Austrosaurus," said Poropat.
"This means that Austrosaurus could potentially be their close relative or even their direct ancestor," he said.
"We can tell that Austrosaurus was at least distantly related to Winton's titanosaurs like Diamantinasaurus and Savannasaurus since it shares some features with them, Poropat said.
The research was published in Alcheringa, an Australasian Journal of Palaeontology.