Friday, 9 March 2012

A New Dinosaur From Australia

The four toed foot of Rhoetosaurus brownei,
possibly the most primitive titanosaur on Earth
For along time, the evolutionary history of Australia during the Mesozoic era has been a mystery. The fossil record is sparse and the fossils which are found are often incomplete. While dinosaurs were the dominant forms of life on the planet, less than 20 species have been found in Australia. Yet palaeontologists from Queensland Museum have now identified a new species from the old collections in the museum's vaults.

In 1924, a team of stockmen uncovered a series of gigantic, mysterious bones 50 kilometres north of the town of Roma, western Queensland, Australia. They believed the bones to be from an elephant which had escaped from a circus, but closer examination by palaeontologists at the Queensland Museum revealed them to be from a dinosaur. They were placed in the vaults, named Rhoetosaurus brownei in 1926 by the museum director Heber Longman and then received no attention until several decades later.

A diagram of the skeleton, showing the portions recovered from the desert valley
Earlier this year Jay Nair, a PhD student from the School of Biological Sciences examined the remains. He found that they were from a giant sauropod. The remains have so far been some of the most complete found in Australia. Workmen had returned to the shallow dry valley in 1975 where the bones were discovered, and recovered more pieces of the skeleton. Yet these remained unprepared. It was only when Nair and his team cleaned and prepared them  remains that they realized how important the find was.

Their study, focusing mainly on the legs and feet shows that Rhoetosaurus was a primitive sauropod. Most of the giant plant eaters have three, clawed feet. This new beast has four, showing that it is quite archaic, despite its comparatively young age of 165 million years. Nair and his team concluded that it was a species of titanosaur, the last ever group of giant sauropods to evolve on Earth before the extinction of the dinosaur 65 million years ago.

Rhoetosaurus is 5 million years older than any other titanosaur species on Earth, possibly making it the ancestor of all others. 'It's great to see this new research being conducted on Rhoetosaurus,' said Dr Andrew Rozefelds, Head of Geosciences at the Queensland Museum. 'It highlights the fact that as our knowledge of dinosaurs increases, so too does the need to revisit museum collections to reexamine old discoveries.' Rhoetosaurus was the first dinosaur to go into the museum's collections. It's rather neat that it is now providing new clues as to Queensland's unique prehistory.