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

New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley
Artist's impression of a Galleonosaurus dorisae herd on a riverbank in the Australian-Antarctic rift valley during the Early Cretaceous, 125 million years ago. The newly-named, dinosaur wallaby-sized herbivorous dinosaur, was identified from five fossilized upper jaws in 125-million-year-old rocks from the Cretaceous period of Victoria, southeastern Australia. Credit: Image copyright James Kuether

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 Ph.D. 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.

New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley
Fossils and 3D CT model of the newly named dinosaur, Galleonosaurus dorisae. The 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. Credit: Matthew Herne

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 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 3-D 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 from other continents."


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More information: 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
Journal information: Journal of Paleontology

Citation: New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley (2019, March 11) retrieved 16 July 2019 from https://phys.org/news/2019-03-wallaby-sized-dinosaur-ancient-australian-antarctic-rift.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Mar 11, 2019
The artists impression shows the deeply indoctrinating paradigm in full regalia. There are only dinosaurs to be seen, no birds, no ducks, no geese, no foxes, no dogs, no goats, sheep, crocodiles, lizards, hares, platypuses, whales, sharks or even octopus and squid.
Why do I mention those? Because just about all dinosaur fossil beds have some one or other of those items mixed in with them and what I mentioned is just a small list.
It is a deep dark secret among the paleontologists that those other creatures are absolutely not to be mentioned in the same breath as dinosaurs - rather give them some other newly coined species even though they look exactly like their modern counterparts which will then remain completely isolated from the dinosaurs. Talk about sleight of hand. Whether they do it on purpose or because of self-seeking acclamation I'm not sure. But the practice is solidly standard.

Mar 11, 2019
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.

Note that this is simply a made-up story completely devoid of truth - no one was there to witness and record this supposed event and hence anything goes.
Since they saw tree trunks mixed in with the bones, did anyone consider doing a C14 analysis of the remains ( fossilized or not ) to ascertain if there was ANY C14 left? The obvious answer is NO, because it would be an expensive test to perform that might have some highly challenging results that need to be explained away. So rather go with the standard assumption that "no such C14 content could have remained intact over millions of years". Why go looking for trouble?

Mar 11, 2019
@FreddyJoe doesn't "believe in" dinosaurs. This is what it believes in: https://pbs.twimg...pg:large

Mar 11, 2019
Another article that refutes YEC claims, another strawman pile of excrement out of Fred. Yawn.

Mar 11, 2019
This comment has been removed by a moderator.

Mar 11, 2019
uhh, freddy my boy. You really need to reconsider that gibberish you just spouted. I've told you before, you need a professional editor.

Cause your logic train not only ran off the tracks but took a flying leap off the wharf into the bay!

If I did not know that you were a YEC looneytoons? I would assume you meant that various bones were a display of the accurate predictions of Scientific Evolutionary Theory.

Showing in detail the ancestral forms of modern Avian species,

Are you as drunk as Noah?
Forgetting to let aboard the ark, the dragons. leviathans, & all the other fabulous Cryptozoic creatures lost to the little, ittybitty, insignificant, very localized flood?

Cause the drunk waited for polar bears, penguins & platypus to get aboard?
But abandoned to drown, that noble symbol of purity the unicorns?

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