(CNN) How did the dinosaurs cross from South America to Australia?

The discovery of two new dinosaur skeletons helped fill in that mystery, according to research published this week in Scientific Reports.

Both sets of fossils found in Australia are titanosaurs , a type of dinosaur believed to be the largest, land-living animals of all time.

Long before those fossilized creatures were alive about 95 million years ago, their ancestors migrated during the mid-Cretaceous Period as dinosaurs spread worldwide. Scientists believe the climate was warmer, making the polar areas much easier to traverse.

"Australia and South America were connected to Antarctica throughout much of the Cretaceous," Paul Upchurch, professor of paleobiology at the University College London, said in a statement.

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Scientists used new information gleaned from the fossils to look further into dinosaur genetics, migration and habitat. Upchurch and his colleagues concluded that the ancestors of the two recently discovered skeletons came to Australia by way of a Patagonia-West Antarctica land connection more than 100 million years ago.

The crossing became easier around 105 million years ago as a warming period removed the barrier between Antarctica and South America.

Dinosaurs Down Under

The two recently discovered fossils are the Diamantinasaurus matildae , the first cranial remains found of an Australian dinosaur, and the Savannasaurus elliottorum , nicknamed Wade -- a new species.

The latter's name comes from the savannah where it was found and the man who discovered the fossils.

In 2005, David Elliott, co-founder of the Australian Age of Dinosaurs Museum , had been gathering his sheep when he spotted a small pile of fossil bone on the ground.

Both fossils are on display at the Australian museum in Winton in Queensland.