The neck vertebra discovered on the south-west coast six years ago has been identified as a spinosaur by a team of palaeontologists and sheds new light on the evolutionary history of the creature.

Measuring around 4cm in length, the neck vertebra belonged to a small spinosaur around two metres long, which lived about 105 million years ago during the Early Cretaceous period.

The team's findings, published yesterday in Biology Letters, break from previous thinking that 'spine lizard' dinosaurs were restricted to specific regions and suggests the animal once roamed the globe.

Museum Victoria senior curator Tom Rich said spinosaurs were previously known to be from Europe, Africa and South America.

"The fact that they existed in Australia changes our understanding of the evolution of this group of dinosaurs," Dr Rich said.

"The existence of this neck vertebra adds to the view that in the Early Cretaceous period, the dinosaur faunas found in many other parts of the world were also found in Australia."

Along with recent discoveries of other dinosaur groups in Australia that were previously thought to be restricted to the northern hemisphere, evidence is growing for the worldwide distribution of dinosaur faunas.

"The same groups of dinosaurs were widespread when the Earth was once a supercontinent," Dr Rich said.

"When the Earth evolved into separate continents, the various families of dinosaurs had already reached those landmasses, which explains why the same ones have been found in places now far apart from one another."

The fossil was discovered by Michael Cleeland and George Caspar near the lighthouse in Victoria in 2005.

It was later identified by the paper's lead author, Dr Paul Barrett from the Natural History Museum in London.

The analysis was carried out by him working in conjunction with co-authors Dr Roger Benson of the University of Cambridge, Dr Thomas Rich from Museum Victoria and Professor Patricia Vickers-Rich of Monash University.

Dr Rich and his US colleague Anthony Martin located at least 24 dinosaur prints along the coast last year near Cape Otway, which was the most significant cluster discovered in Victoria.

Boulders containing the prints were transported to Museum Victoria last week for analysis, with the findings expected to be published next month.

Dr Rich also uncovered evidence that tyrannosaur dinosaurs existed in the southern hemisphere after finding a fossil at Dinosaur Cove near the Otway coast in 1989.

sfowles@standard.fairfax.com.au