Multiple bizarre new giant kangaroo species discovered in Australia

Scientists have discovered three extinct giant kangaroo species in Australia and New Guinea, furthering our understanding of the evolution and distribution of these marsupials.

All three species belong to the now-extinct genus Protemnodon and lived from around 5 million to 40,000 years ago.

One of these species was about double the size of the largest red kangaroo living today. Named Protemnodon viator – Latin for “traveller” – it adapted well to its arid central Australian habitat and weighed up to about 170 kg. The other two species weighed around 50 kg.

Researchers, including from Flinders University, identified the new species based on complete fossil kangaroo skeletons unearthed at Lake Callabonna in South Australia in 2013, 2018 and 2019.

They found that these species were squat and muscular and looked somewhat similar to the grey kangaroos we see today. Each adapted to live in different environments and even hopped in different ways.

“The different species of Protemnodon are now known to have inhabited a broad range of habitats, from arid central Australia to the high-rainfall, forested mountains of Tasmania and New Guinea,” Isaac Kerr, one of the researchers, said.

Researchers suspect that one of the newly discovered species, Protemnodon mamkurra, walked on four legs at times and hopped on two at others.

“A large but thick-boned and robust kangaroo, it was probably fairly slow-moving and inefficient. It may have hopped only rarely, perhaps just when startled,” they said.

The name, mamkurra, means “great kangaroo” and it was chosen by elders at Green Waterhole Cave in South Australia on the land of the indigenous Boandik people.

All Protemnodon and closely related animals like the wallaroos went extinct on mainland Australia about 40,000 years ago but likely lingered a bit longer in New Guinea and Tasmania.

“Living kangaroos are already such remarkable animals, so it’s amazing to think what these peculiar giant kangaroos could have been getting up to,” Dr Kerr said.