The Puzzling Puzzle of Australia's Giant Fossil Kangaroos

Sunday - April 28 2024, 09:09 UTC - 6 months ago

The discovery of new species of giant fossil kangaroos in Australia and New Guinea has revealed greater diversity in their form, geographic distribution, and locomotion. The newly described Protemnodon viator was twice the size of the largest living red kangaroo and was well-adapted to its arid environment. The species varied in size and movement, with one species hopping like quokkas or potoroos and another species likely moving on four legs. Lead researcher Dr Isaac Kerr revisited the work of British naturalist Sir Richard Owen, who coined the term 'dinosaur'.

Researchers at Flinders University have identified three unusual new species of giant fossil kangaroo from Australia and New Guinea, revealing greater diversity in their form, geographic distribution, and locomotion than was previously recognized. The discovery of multiple complete fossil kangaroo skeletons from Lake Callabonna in arid South Australia in 2013, 2018, and 2019, has allowed lead researcher Dr Isaac Kerr, to unpick a nearly 150-year-long puzzle around the identities of the species of Protemnodon .

The new Flinders University study reviewed all species of Protemnodon, finding that they were quite different from one another and adapted to live in differing environments. While some species were around 50 kg, others were much larger than any living kangaroo. However, one new species named as part of the latest study - Protemnodon viator - was much bigger, weighing up to 170 kg. This is about twice as much as the largest male red kangaroos .

Protemnodon viator was well-adapted to its arid central Australian habitat, living in similar areas to the red kangaroos of today. It was a long-limbed kangaroo that could hop fairly quickly and efficiently. Its name, viator, is Latin for 'traveler' or 'wayfarer'. The Australian researchers discovered two other new species - Protemnodon mamkurra and Protemnodon dawsonae - while also revisiting the work of earlier researchers including British naturalist Sir Richard Owen who coined the term 'dinosaur' in Victorian England .

The first species of Protemnodon were described in 1874 by British paleontologist Owen who focused chiefly on fossil teeth. He saw slight differences between the teeth of his specimens, and described six species of Protemnodon. The new Flinders University study agrees with one of his species, Protemnodon anak. This first specimen described, called the holotype, still resides in the Natural History Museum in London .

Dr Kerr says it was previously suggested that some or all Protemnodon were quadrupedal, but this study suggests that this is only true for three or four species. The newly described Protemnodon mamkurra was likely one of these quadrupedal species, with a large but thick-boned and robust body that may have been slow-moving and hopped only rarely.