New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley

A new, wallaby-sized herbivorous dinosaur has been identified from five fossilized upper jaws in 125 million year old rocks from the Cretaceous period of Victoria, southeastern Australia.

Reported in the Journal of Paleontology, the new dinosaur is named "Galleonosaurus dorisae," and is the first dinosaur named from the Gippsland region of Australia in 16 years. According to Dr Matthew Herne, a Postdoctoral Fellow at the University of New England, NSW, and lead author of the new study, "the jaws of Galleonosaurus dorisae include young to mature individuals--the first time an age range has been identified from the jaws of an Australian dinosaur."

Galleonosaurus was a small-bodied herbivorous dinosaur within the large family called ornithopods. "These small dinosaurs would have been agile runners on their powerful hind legs," explained Dr Herne.

The name Galleonosaurus dorisae refers to the shape of the upper jaw, resembling the upturned hull of a sailing ship called a galleon, and also honours the work of Dr Doris Seegets-Villiers, who produced her PhD thesis on the palaeontology of the locality where the fossils were discovered.

Galleonosaurus is the fifth small ornithopod genus named from Victoria, which according to Dr Herne, "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." Small ornithopods appear to have thrived on the vast forested floodplain within the ancient rift valley.

At the time of Galleonosaurus, sediments were shed from a four thousand km long massif of large, actively erupting volcanoes that once existed along the eastern margin of the Australian continent. Some of these sediments were carried westward by large rivers into the Australian-Antarctic rift valley where they formed deep sedimentary basins. However, as these sediments washed down the rivers of the rift valley the bones of dinosaurs, such as Galleonosaurus and other vertebrates, along with the logs of fallen trees, became mixed in. According to Dr Herne, "this land has now vanished, but as 'time-travellers' we get snapshots of this remarkable world via the rocks and fossils exposed along the coast of Victoria."

The new article shows that Galleonosaurus dorisae is a close relative of Diluvicursor pickeringi; another small ornithopod named by Dr Herne and his team in 2018, from excavations along the Otway coast to the west of the Gippsland region. Interestingly, "the jaws of Galleonosaurus and the partial skeleton of Diluvicursor were similarly buried in volcanic sediments on the floor of deep powerful rivers," explained Dr Herne. "However, Galleonosaurus is about 12 million years older than Diluvicursor, showing that the evolutionary history of dinosaurs in the Australian-Antarctic rift had been lengthy."

The jaws of Galleonosaurus were discovered by volunteers of the Dinosaur Dreaming project during excavations near the town of Inverloch. The most complete jaw and the key specimen carrying the name Galleonosaurus dorisae was discovered in 2008 by the seasoned fossil hunter Gerrit ('Gerry') Kool, from the nearby town of Wonthaggi. Gerry and his wife Lesley have been instrumental in organizing the Dinosaur Dreaming excavations along the Victorian coast for 25 years.

Prior to discovery of Galleonosaurus dorisae, the only other ornithopod known from the Gippsland region was Qantassaurus intrepidus, named in 1999. However, Qantassaurus had a shorter more robust snout than that of Galleonosaurus, explained Dr Herne, who added, "we consider that these two, similarly-sized dinosaurs fed on different plant types, which would have allowed them to coexist."

The new study reveals that the ornithopods from Victoria are closely related to those from Patagonia in Argentina. "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," added Dr Herne

These are exciting times for dinosaur research, explained Dr Herne: "Using advanced techniques, such as 3D micro-CT scanning and printing, new anatomical information is being revealed on dinosaurs such as Galleonosaurus dorisae. These techniques are helping us to delve deeper into 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."

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Images and a PDF copy of the paper are available on request.

Contacts:
John Clare, Communications Manager, Cambridge University Press
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Notes to editors:

1. Paper details: New small-bodied ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic rift system, with revision of Qantassaurus intrepidus Rich and Vickers-Rich, 1999. Matthew C. Herne, Jay P. Nair, Alistair R. Evans, and Alan M. Tait. Journal of Paleontology (2019). DOI: 10.1017/jpa.2018.95

2. About the author: Dr Matthew (Matt) Herne is a vertebrate palaeontologist whose main research focus is on Australian dinosaurs. He is currently a Postdoctoral Fellow at the University of New England in Armidale, New South Wales, where he is investigating the functional anatomy and phylogenetics of Australian ornithopod dinosaurs, such as the iconic large-bodied taxon Muttaburrasaurus. In 2018, Matt named the new small-bodied ornithopod Diluvicursor pickeringi from Victoria (PeerJ) and was a co-author on a Journal of Vertebrate Paleontology (JVP) monograph detailing the remarkable dinosaur trackways in Broome, Western Australia. Matt also has a museum curatorial and hands-on exhibits background. He helped set up the new Philip J. Currie Dinosaur Museum in Alberta, Canada (2015), and has worked on recreating the skeletons of dinosaur giants, such as 'Seismosaurus', for museum displays globally.

3. About the Journal of Paleontology: The Journal of Paleontology is a journal of the Paleontological Society. It publishes original articles and notes on the systematics, phylogeny, paleoecology, paleogeography, and evolution of fossil organisms. It emphasizes specimen-based research and features high quality illustrations. All taxonomic groups are treated, including invertebrates, microfossils, plants, vertebrates, and ichnofossils.

4. About the Paleontological Society: The Paleontological Society is an international nonprofit organization devoted exclusively to the advancement of the science of paleontology: invertebrate and vertebrate paleontology, micropaleontology, and paleobotany. The Society was founded in 1908 in Baltimore, Maryland, and was incorporated in April 1968 in the District of Columbia. The Society has several membership categories, including regular, student, and retired. Members, representing 40 countries, consist of professional paleontologists, academicians, science editors, earth-science teachers, museum specialists, and undergraduate and graduate students and post-doctoral scholars, as well as avocational paleontologists.

5. About Cambridge University Press: Cambridge University Press is part of the University of Cambridge. It furthers the University's mission by disseminating knowledge in the pursuit of education, learning and research at the highest international levels of excellence. Its extensive peer-reviewed publishing lists comprise 50,000 titles covering academic research and professional development, as well as school-level education and English language teaching. Playing a leading role in today's international marketplace, Cambridge University Press has more than 50 offices around the globe, and it distributes its products to nearly every country in the world.

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