The remains of two gigantic dinosaurs discovered in Australia may shed light on how dinosaurs spread across the globe.

The dinosaurs are both titanosaurs, massive plant-eaters with long necks and thick limbs. The first, a new species known as Savannasaurus elliottorum, was about half the length of a basketball court and lived about 95 million years ago during the Cretaceous period. Paleontologists also found the skull of a Diamantinasaurus matildae, which grew longer than a city bus and was first identified in 2009 based on fossils in the same region as these latest finds.

"These dinosaurs were co-existing happily, or so it would seem," Stephen Poropat, a paleontologist at the Australian Age of Dinosaurs Museum of Natural History in Winton, Australia, said in a video interview.

The fossils may help explain how giant plant-eaters migrated across the Earth. According to researchers, the titanosaurs' features indicate they are likely descendants of dinosaur lineages that originated in South America. At the time, South America and Australia were connected to the modern-day continents of Africa and Antarctica. The dinosaurs could have migrated across either way, but based on the age of the bones, the authors believe the most likely route was south across Antarctica.

The migration likely took place during a period of prehistoric global warming, the researchers say. Over the millions of years that followed, the continents slowly drifted apart, separating the dinosaur species.

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