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Friday, June 10, 2011

Australia: Walking in their footsteps on Victoria's dinosaur trail

theage.com.au: Walking in their footsteps on Victoria's dinosaur trail
THE most significant cluster of dinosaur footprints in Victoria has been discovered about 100 kilometres from Melbourne. Dating back about 105 million years to the early Cretaceous period, they represent up to 90 per cent of the known dinosaur footprints in the state, according to Museum Victoria senior curator Tom Rich.

A palaeontologist, Dr Rich discovered the footprints with US colleague Anthony Martin at Melanesia Beach, near Cape Otway, in June last year.

''Tony and I did what he'd dubbed 'the great cretaceous walk','' Dr Rich said. ''We started at Inverloch and walked the coastline to San Remo. And then we started again at Apollo Bay and walked west to Moonlight Head.''

Advertisement: Story continues below The two adopted a strategic approach to their month-long coastline search for trace fossils, which can come in the form of footprints, scratch marks or burrows, and are evidence of activity by living organisms.

The pair located at least 24 prints on the windswept shoreline. Before this, only four confirmed dinosaur tracks had been found in Victoria.

While recognisable only to the trained eye - as faint depressions in the sandstone - the prints have excited researchers who spent many months puzzling over how to extract them without damaging them. Left as they were, the footprints would have eroded within a decade, Dr Rich said, due to the harsh conditions.

Working with Parks Victoria and local landowner Greg Denney, Dr Rich co-ordinated the removal of two blocks - the heaviest weighing 700 kilograms - which were transported to Museum Victoria last week. Scientists at the museum will make silicone surface moulds of the footprints for study and possible display.

''Bones tell us how animals were buried,'' Dr Rich said. ''But trace fossils of any kind are interesting; they tell us how they were living. It's the difference between a living scene and a cemetery, essentially.''

Dr Martin, from Emory University's environmental studies department in Atlanta, Georgia, is studying the prints to establish their age, the type of dinosaur that made them and whether they were made by more than one animal. His findings will be published next month in the journal Alcheringa: An Australasian Journal of Palaeontology.

''This dinosaur track assemblage is the best in terms of numbers and quality found thus far in formerly polar environments of the southern hemisphere,'' Dr Martin said.

The prints vary in size, suggesting they were made by a variety of dinosaurs. He said the prints included what appeared to be a dinosaur trackway - three consecutive tracks in sequence made by the same dinosaur. If this proves correct, it would be the first known dinosaur trackway from the Cretaceous period in Victoria.

Much of what is known about the local fauna of the Cretaceous period comes from fossil beds in Victoria's two premier dinosaur sites: Dinosaur Cove - 10 kilometres from Melanesia Beach - and Flat Rocks, near Inverloch.

The Earth during this period was warmer than it is now, making the polar regions more habitable, with forests extending to the South Pole.

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