Australia is well known for its unique and diverse wildlife, especially its extinct megafauna.
Among these ancient giants was a group of herbivorous marsupials called diprotodontids, which ranged in size from a small dog to a car.
A new study by researchers from Flinders University and the University of St Andrews has revealed a previously unknown species of diprotodontid that was adapted to walk long distances in search of food and water.
What was this new species and how was it discovered?
JUAN MABROMATA/AFP via Getty Images
The new species, named Ambulator keanei, meaning walker or wanderer, belongs to the family Diprotodontidae, which includes the largest marsupials that ever lived, such as the rhino-sized Diprotodon, as per Phys.org.
Ambulator keanei was about the size of a cow, weighing about 250 kilograms.
It lived about 3.5 million years ago in the Pliocene epoch when Australia was becoming drier and more arid.
The partial skeleton of Ambulator keanei was found on the Australian Wildlife Conservancy's Kalamurina Station in northern South Australia by Flinders University researchers in 2017.
The skeleton was eroding from a cliff face on the Warburton River and consisted of bones from the skull, jaw, neck, back, limbs, and feet.
The researchers used advanced 3D scanning and other technology to analyze the bones and compare them with other diprotodontids.
They found that Ambulator keanei had distinctive features in its legs and feet that indicated it was well suited to walking long distances across the arid landscape.
It had long and robust limbs, large and flat heel bones, and reduced toes that did not touch the ground.
These adaptations made it more efficient and stable when walking on uneven terrain.
The researchers also used CT scanning to reveal soft tissue impressions inside the foot bones, giving them an insight into the structure of the animal's footpad.
They found that Ambulator keanei had a plantigrade stance, meaning it walked with its heels on the ground, similar to humans.
It also had a modified wrist bone that formed a secondary heel on its hand, which helped to distribute its weight.
Why is this discovery important and what does it tell us?
The discovery of Ambulator keanei adds to our knowledge of the diversity and evolution of diprotodontids, which were an important part of Australian ecosystems until they became extinct about 40,000 years ago, as per The New Daily.
The researchers suggest that Ambulator keanei represents a new genus of diprotodontid that evolved in response to the changing climate and environment of Australia.
Ambulator keanei shows that diprotodontids were able to adapt to different habitats and lifestyles, ranging from forest dwellers to open plain wanderers.
It also showed that diprotodontids were able to cope with the challenges of living in arid regions, such as finding enough food and water.
The researchers hope that their study will inspire more research on the biology and behavior of diprotodontids, which is largely unknown.
They speculated that Ambulator keanei may have used vocalizations to communicate with other members of its species over long distances, as well as to avoid predators and locate resources.
The researchers also hope that their study will raise awareness of the conservation issues facing the modern wildlife of Australia, which is facing similar threats as their ancient relatives.
They urge more support for the protection and restoration of habitats for native animals, especially in arid regions.
Diprotodontids are an extinct family of large herbivorous marsupials that were endemic to Australia and New Guinea during the Oligocene through Pleistocene periods from 28.4 million to 40,000 years ago.
They were the largest marsupials that ever lived, with some species reaching up to 2.7 tons in weight.
They belonged to the order Diprotodontia, which also includes living marsupials such as kangaroos, wallabies, possums, koalas, and wombats.
Diprotodontids were an incredibly diverse group of animals that occupied various ecological niches.
Some were capable of climbing trees, some had large cheekbones for storing food, some had specialized teeth for grinding tough plants, and some were carnivorous predators.
They played an integral role in Australian ecosystems until they became extinct due to human activities or environmental changes.
Ambulator keanei is one of the most recent discoveries among diprotodontids.
It is a new genus and species that was described based on a partial skeleton found in northern South Australia in 2017.
It is remarkable for its adaptations for walking long distances across arid landscapes, which may have helped it survive in a changing climate.
It is also one of the few diprotodontids with preserved soft tissue structures, which provide valuable information on its anatomy and physiology.
