Scientists Unveil New Genus of Diprotodontid Marsupial
Utilizing cutting-edge 3D scanning technology, paleontologists from Flinders University have made a significant breakthrough in understanding the remains of a marsupial dating back 3.5 million years in Central Australia. This ancient creature, now identified as one of Australia’s earliest long-distance walkers, has been classified as a new genus of diprotodontid named Ambulator, meaning walker or wanderer. The advanced adaptations in its legs and feet suggest that this quarter-tonne animal was well-equipped to traverse vast distances in search of sustenance and water.
The skeleton, identified as Ambulator keanei, was discovered in 2017 by Flinders University researchers on the Kalamurina Station of the Australian Wildlife Conservancy in northern South Australia. It belongs to the Diprotodontidae family, a group of herbivores that were the largest marsupials to have roamed the Earth. Diprotodontids, distantly related to wombats and as distinct from kangaroos as they are from possums, have posed challenges for paleontologists attempting to reconstruct their biology.
During the Pliocene era, the time when Ambulator keanei existed, Australia experienced a shift towards drier conditions, resulting in the emergence of grasslands and open habitats. As a consequence, diprotodontids likely had to travel extended distances to secure enough food and water to sustain themselves. Considering their large size, efficiency in movement became crucial due to the energetic costs involved.
Most large herbivores today, such as elephants and rhinoceroses, adopt a digitigrade walking style, with their heels elevated from the ground. In contrast, diprotodontids, like humans, exhibit a plantigrade stance, where the heel contacts the ground while walking. This weight distribution strategy requires more energy but provides advantages for other activities, such as running.
Furthermore, diprotodontids possess a unique adaptation in their hands, involving the modification of a wrist bone called the pisiform into a secondary heel. This peculiar feature led to early reconstructions of these animals appearing awkward and peculiar. The restructuring of the wrist and ankle bones allowed for efficient weight-bearing, enabling diprotodontids to grow remarkably large.
The recently described partial skeleton of Ambulator keanei holds immense scientific value, as associated skeletons are rarely found in the fossil record. Its significance is further heightened by the presence of preserved soft tissue structures, making it the first such discovery of its kind. Through the application of 3D scanning technology, the Flinders research team compared the partial skeleton with diprotodontid material sourced from collections worldwide.
The foot of the individual was encased in a solid concretion that formed soon after its demise. By employing CT scanning, researchers unveiled soft tissue impressions that retained the footpad’s outline. These findings shed light on the locomotory adaptations and evolutionary path of Ambulator and its relatives.
Funding for this research was provided by the Australian Government Research Training Program Scholarship (Excellence). The researchers also received partial financial support from the Royal Society of South Australia small grant scheme 2018, the University of California Museum of Paleontology Doris O. and Samuel P. Welles Fund 2019, Flinders University Higher Degree Research International Conference Travel Grant 2019, and the North American Paleontology Conference Student Travel Grant. The Flinders University team expresses gratitude to Tess McLaren and Keith Bellchambers from the Australian Wildlife Conservancy for their assistance in the field at Kalamurina Station.
Frequently Asked Questions (FAQs) about Long-distance walker
What is the significance of the discovery of Ambulator keanei?
The discovery of Ambulator keanei is significant because it provides new insights into the ancient marsupial species in Australia. It is identified as one of the first known long-distance walkers in the country, shedding light on the evolutionary adaptations and locomotory abilities of diprotodontids.
How was Ambulator keanei identified?
Ambulator keanei was identified through the use of advanced 3D scanning technology. Paleontologists from Flinders University employed 3D scans and compared the partial skeleton with other diprotodontid material from collections around the world to determine its classification.
What is the meaning of the name “Ambulator”?
“Ambulator” is a name derived from Latin, meaning walker or wanderer. It was chosen to reflect the locomotory adaptations of the legs and feet of this ancient marsupial, suggesting its ability to roam long distances in search of food and water.
How does the walking style of diprotodontids differ from other large herbivores?
Diprotodontids, including Ambulator keanei, exhibit a plantigrade walking style, similar to humans, where their heel bone contacts the ground while walking. This is in contrast to digitigrade walking seen in large herbivores like elephants and rhinoceroses, where they walk on the tips of their toes with their heel elevated.
What makes Ambulator keanei unique compared to other diprotodontids?
Ambulator keanei is unique because it represents the first diprotodontid skeleton to be found with associated soft tissue structures. This discovery provides valuable insights into the anatomy and locomotion of these ancient marsupials, which were the largest marsupials to have existed.
More about Long-distance walker
- Journal of Royal Society Open Science – Description of the Pliocene marsupial Ambulator keanei gen. nov. (Marsupialia: Diprotodontidae) from inland Australia and its locomotory adaptations
- Flinders University – Paleontology Laboratory
- Australian Wildlife Conservancy
- University of California Museum of Paleontology
- Royal Society of South Australia
- North American Paleontology Conference