A new dinosaur species that lived 125 million years ago has been discovered in Australia, one so small, it was likely the size of a wallaby. The size of the jaw bones indicate that this new species was relatively small-"wallaby-sized", as the researchers put it.
"These small dinosaurs would have been agile runners on their powerful hind legs", lead study author Matthew Herne, a postdoctoral fellow at the University of New England, said in a statement. Herne says this "confirms that on a global scale, the diversity of these small-bodied dinosaurs had been unusually high in the ancient rift valley that once extended between the spreading continents of Australia and Antarctica".
Herne & Co. classified the dinosaur based on five fossilized upper jaws-from young to mature individuals-found in rocks from Bunurong Marine Park in Australia.
The scientists named the species Galleonosaurus dorisae, after both the galleon and paleontologist Doris Seegets-Villiers, who received her doctorate while working in the area.
Specimens of Galleonosaurus dorisae from the Flat Rocks Sandstone in the upper Barremian, Wonthaggi Formation, Gippsland Basin, southeastern Australia.
Galleonosaurus was also found to be a close relative of Diluvicursor pickeringi, another small ornithopod that was also named by Herne and his colleagues, and found to the west of Gippsland. That rift valley would have provided ample resources for the tiny dinosaurs while also giving them protection from larger predators. "Early flowering plants [were also present], as well as many kinds of ferns and horsetails". But traces of some of the species that once lived there have been preserved, thanks to miles of once-active volcanoes along the rift.
Gallenosaurus was buried in volcanic sediments carried by what was once a network of deep, swift rivers.
Newly discovered fossils may shed light on a long-vanished land that once connected Australia and Antarctica.
This marks "the first time an age range has been identified from the jaws of an Australian dinosaur", according to Herne.