Scientists discovered a new 'wallaby-sized' dinosaur in Australia

Galleonosaurus dorisae. Image credit James Kuether

Galleonosaurus dorisae. Image credit James Kuether

During the Cretaceous period, as the supercontinent Gondwana was slowly drifting apart, an 1,800-mile rift valley stood between Australia and Antarctica.

Five fossilized upper jaws of the ancient beast were found at the Flat Rocks locality of the Wonthaggi Formation in a region of Gippsland, Victoria, Australia.

As detailed in a new report in the Journal of Paleontology, Galleonosaurus dorisae was a small plant eater that stomped around present-day Australia some 125 million years ago, and it likely used its small stature and impressive legs to duck from the more fearsome predators of the day.

Importantly, the fossil group included specimens from individuals ranging in age from young to mature, marking "the first time an age range has been identified from the jaws of an Australian dinosaur", says Matthew Herne, lead study author and postdoctoral fellow at the University of New England.

Herne told USA TODAY while the dinosaurs would be similar in size to a wallaby, they didn't bear much other resemblance to the furry animals.

Meet the "Galleonosaurus dorisae", or Galleonosaurus for short.

Using 3D micro-CT scans, the researchers were able to take a close at the five jawbones and a tooth, according to Genelle Weule of Australia's ABC News.

Specimens of Galleonosaurus dorisae from the Flat Rocks Sandstone in the upper Barremian Wonthaggi Formation Gippsland Basin southeastern Australia. Scale bars- 10 mm; 1 mm. Image credit Herne et al doi 10.1017/jpa.2018.95

Known as Galleonosaurus Dorisae, this herbivore was found in Victoria, in the southeastern part of the continent.

Galleonosaurus is the fifth ornithopod genus (the classification right above species) identified from Victoria, which "confirms" that these small-bodied dinosaurs were very diverse and thrived in the rift valley that spanned Australia and Antarctica, Herne said. That rift valley would have provided ample resources for the tiny dinosaurs while also giving them protection from larger predators.

Ultimately, the rift was split by the Southern Ocean.

Gallenosaurus was buried in volcanic sediments carried by what was once a network of deep, swift rivers.

By looking at fossils from these basins, experts can also get a better sense of how prehistoric creatures were moving across the globe. With new technologies, he adds, scientists are able to shine unprecedented light on "the mysterious world of dinosaur ecology-what they ate, how they moved and how they coexisted-and their evolutionary relationships with dinosaurs from other continents".

"We are steadily building a picture of terrestrial dinosaur interchange between the shifting Gondwanan continents of Australia, South America and Antarctica during the Cretaceous period", Dr. Herne noted.

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