Ancient large kangaroo mainly used four legs to move

This 'giant wallaby' was a poor hopper.

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A recent study by scientists at the University of Bristol revealed fascinating insights into the extinct “giant wallaby” kangaroo that lived during the Pleistocene around two and a half million to ten thousand years ago.

Contrary to previous assumptions, these large kangaroos, known as Protemnodon, were found to be primarily quadrupedal, using all four legs to move around most of the time. This discovery challenges our previous understanding of these creatures and sheds new light on their locomotion and behavior. The findings, which have been published in the Journal of Mammalian Evolution, offer a captivating glimpse into the ancient world of these remarkable animals.

“There had been some speculation in a graduate thesis from the University of Uppsala that it might have been more quadrupedal in its habits compared to living kangaroos,” lead author Billie Jones, a former Masters student in the Bristol Paleobiology program, explained. “This new paper draws on a couple of previous quantitative studies that looked at the anatomy of the humerus (upper arm bone) in a diversity of mammals and concluded that Protemnodon habitually put more weight on its forelimbs than kangaroos today.”

Previous studies indicated that Protemnodon’s ankle bones were not well-suited for hopping due to the stress they experienced.

The research team demonstrated that the limb proportions of Protemnodon differed significantly from those of modern kangaroos, particularly in its short feet, supporting the hypothesis that it primarily moved on all fours rather than being a specialized hopper like today’s large kangaroos.

This recent publication presents a quantitative analysis of limb proportions and a more qualitative examination of other anatomical features, aiming to confirm the movement patterns of this extinct creature.

The diverse taxonomic characteristics of large kangaroos during the Pleistocene in Australia suggest a corresponding diversity in their ways of movement. Professor Christine Janis from Bristol’s School of Earth Sciences had previously demonstrated that the extinct sthenurines, a distinct subfamily of kangaroos, walked on two legs instead of hopping. This range of movement styles indicates a wider range of environments in the Australian Pleistocene than previously thought, indicating that the continent was not as dry as it is today.

Professor Janis added: “A study of the limb bones, and the bone proportions to each other, show that the so-called extinct’ giant wallaby’, Protemnodon, was likely a poor hopper at best, and probably moved mostly quadrupedally, perhaps bounding on all fours like tree-kangaroos do on the ground.”

Journal reference:

  1. Billie Jones & Christine M. Janis. Hop, walk or bound? Limb proportions in kangaroos and the probable locomotion of the extinct genus Protemnodon. Journal of Mammalian Evolution, 2024; DOI: 10.1007/s10914-024-09725-4

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